Vascular reactivity in reversible experimental obstructive jaundice

We studied the effect of jaundice on in vitro vascular reactivity to cumulative doses of norepinephrine (NE) by measuring the maximal response (Rmax) and the concentration of NE required to cause a 50% response (ED50) of isolated vascular smooth muscle. For this we prepared helically cut strips of thoracic aorta from bile duct ligated (BDL) rats at 1, 3, 6, 14, and 28 days postligation and compared them with those of nonoperated and sham-operated controls. From 1 to 6 days post-BDL, changes in liver blood chemistry and liver histology indicated cholestasis with necrosis. By 14 days, the tests for liver function and histology indicated a return to normal liver function and histology. In nonoperated controls, mean Rmax increased significantly from 883 +/- 67 mg of tension to 1220 +/- 68 mg of tension (P less than 0.0025) from 0 to 28 days, whereas ED50 remained unchanged. In sham-operated controls and BDL rats, an age-dependent increase in Rmax was also observed. However, in the sham groups, ED50 tended to decrease compared with nonoperated controls, indicating a surgically induced "sensitization" phenomenon of the vascular smooth muscle. In contrast, this was not seen in BDL rats since in these groups, the ED50 remained unchanged and significantly higher than in the sham groups, in both the jaundiced (1-6 days) and nonjaundiced (14-28 days) period. Furthermore, these changes occurred in the absence of any alteration in portal pressure. These changes may be important in understanding the mechanism of hypotension and shock in postoperative patients with obstructive jaundice even after the jaundice has been relieved.     

Altered peripheral amino acid uptake in obstructive jaundice

To characterize amino acid metabolism in obstructive jaundice, the amino acid uptake in tissues of bile duct-ligated (BDL) rats was determined. Fischer 344 rats underwent either bile duct ligation or sham laparotomy and were pair fed for 72 hr. Amino acid uptake was determined in peripheral skeletal muscle (quadriceps femoris, soleus, and rectus abdominis), liver, blood, and other tissues by accumulation of alpha-[14C]-aminoisobutyric acid following intracardiac injection. Although total hepatic amino acid uptake was unaltered in the BDL animals compared with the sham-operated controls, amino acid uptake in peripheral skeletal muscle was significantly decreased in all muscle groups studied in the BDL rats. The relative concentration (percentage dose per gram normalized to the animal mass) for quadriceps femoris was 0.16 +/- 0.02 for BDL and 0.32 +/- 0.04 for sham-operated rats, P less than 0.005. Muscle protein was lower in BDL animals when compared with sham-operated rats (P less than 0.05). Total trunk blood amino acid levels were not significantly different in the two groups; however, there was a decreased serum level of branched-chain amino acids in the BDL group, P less than 0.05. No differences in plasma glucose or serum insulin were found in the two groups; lactate levels were lower in the BDL group, and plasma triglyceride levels were three times higher in the BDL animals. These data suggest that obstructive jaundice in the rat is associated with organ-specific metabolic abnormalities consistent with impaired peripheral amino acid uptake.     

Treatment with recombinant bactericidal/permeability-increasing protein to prevent endotoxin-induced mortality in bile duct-ligated rats.

BACKGROUND: Operation in patients with obstructive jaundice is associated with substantial morbidity because of increased susceptibility to endotoxin (lipopolysaccharide) and the inflammatory cascade. Different interventions to reduce endotoxemia and cytokine induction, and resulting complications, have been studied. Bactericidal/permeability-increasing protein (BPI) is a naturally occurring endotoxin-binding protein produced in neutrophils. It binds endotoxin, neutralizing the activity and inhibiting cytokine production by mononuclear cells. In experimental endotoxemia in animals and in healthy human volunteers, BPI has shown a protective effect. The aim of this study was to determine whether BPI could protect against increased endotoxin sensitivity in rats with obstructive jaundice and reduce endotoxin-induced mortality. STUDY DESIGN: Male Wistar rats were used. Intraperitoneal Escherichia coli 2mg/kg was given 1 week after sham operation or bile duct ligation (BDL). Three groups were studied: sham, BDL with placebo, and BDL with 5 mg/kg recombinant BPI21. RESULTS: BDL rats were jaundiced (mean bilirubin 186 micromol/L; no difference between BDL rats without or with BPI). Bilirubin remained less than 1 micromol/L in sham-operated rats (p = 0.002). Endotoxin levels were 3.4pg/mL in sham controls and 3.1 pg/mL in BDL rats before administration of lipopolysaccharide (p = NS). Two hours after administration, levels were 615.4ng/mL in placebo BDL rats and 10 times less in BPI-treated BDL rats, at 60.2ng/mL (p=0.03). The same trend was found at 6 hours. At 24 hours, mortality was 1 of 6 in sham-operated rats (15%) versus 8 of 11 in untreated BDL rats (75%). BPI intervention reduced the death rate to 1 of 12 BDL rats (8%) (p = 0.003). CONCLUSIONS: Intraperitoneal recombinant BPI21 in rats having BDL reduced endotoxin-induced mortality from 75% to 8%, a death rate comparable to that in nonjaundiced rats. BPI could be an interesting perioperative treatment in clinical obstructive jaundice.     

The effect of truncal vagotomy on serotonin distribution in the rat gastrointestinal tract

The 5-HT levels in biopsies from the rat gastrointestinal tract were measured by a sensitive liquid chromatography method with electrochemical detection. The highest levels were found in the gastroduodenal and cecal regions. Sham-operated controls were compared with rats subjected to combined truncal vagotomy and pyloroplasty or pyloroplasty alone 5 weeks after surgery. Significantly decreased 5-HT levels were demonstrated in animals subjected to vagotomy + pyloroplasty or to pyloroplasty alone, compared with sham-operated controls. In the upper gastrointestinal tract of vagotomized animals significantly decreased 5-HT levels were found when compared with animals subjected to pyloroplasty alone. However, anesthesia and surgery (sham operation) per se markedly increased 5-HT levels of the gut even 5 weeks postoperatively, when compared with acutely killed rats. The underlying mechanism is still obscure. However, vagotomy largely prevented this increase. Therefore, the importance of correct controls is emphasized, since previous investigations claim to have demonstrated increased 5-HT levels in vagotomized animals, when compared with nonoperated controls.     

Neurotransmitter amines in brain edema of a rat glioma model

The effect of vasogenic brain edema on amine neurotransmitter concentrations was studied in rats bearing transplanted glioma C6 brain tumors. In comparison with sham-operated and nonoperated controls, the tumor-implanted animals showed significant decreases in both dopamine (DA) and norepinephrine (NE) in the hypothalamus, cortex, and striatum. Treatment with dexamethasone (DEX) tended to restore these monoamines to the levels measured in sham-operated controls. In the nonoperated controls, DEX significantly increased NE but not DA. In tumor-bearing rats there was no increase in hypothalamic or striatal water content, and DEX had no effect on the water content of these structures. However, there was a significant increase in the cortical water content, which was reduced by DEX to the control levels. The water content within the tumor was also significantly decreased by DEX. In the nonoperated controls, there was no difference in water content between DEX-treated and nontreated animals. These findings suggest that tumor-induced brain edema reduces noradrenergic and dopaminergic activities. DEX administration resulted in normalization of the water content in edematous regions and of the DA and NE concentrations, and brought about marked symptomatic improvement.     

Influence of the uremic state on the development of malignancy. An experimental study in the rat

The effect of chronic uremia on the development of subcutaneously injected malignant tumoral cells was evaluated in 213 male Wistar AG rats made chronically uremic by simultaneous right nephrectomy and partial ligation of the left renal artery. The tumoral cells injected were stemming from a parental rhabdomyosarcoma (9-4/0) induced by intramuscular injection of 20 mg of colloidal nickel suspended in oil to a male Wistar rat. 54 sham-operated rats and 43 nonoperated animals served as control-groups. Renal function and tumoral growth were checked weekly up to the 60th postoperative day, at which time the surviving rats were sacrificed and submitted to autopsy. At day 15 after cell grafting, a tumoral lump could be felt by finger touch in 68% of the uremic rats, but in only 11% of the sham-operated and 14% of the nonoperated controls (p less than 0.0001). Throughout the study, the tumoral lumps which developed in the uremic animals were of significantly larger size than in the nonuremic controls. Pulmonary tumoral metastases were evidenced at autopsy in 95% of the uremic rats, but in only 50% of the sham-operated and in 54% of the nonoperated controls (p less than 0.005). These results indicate an apparently accelerating and amplifying effect of uremia on the development of a malignant tumor in the rat, for which a decrease in cell-mediated immunity associated with the uremic state still remains a questionable hypothesis.     

Does the analysis based on a histological and immunohistochemical grading system in the model of BDL kidney allow the quantification of the degree of injury?

The aim of this study is to evaluate histopathological findings induced by Nomega-nitro-L-arginine methyl ester (L-NAME) and molsidomine (MOL) on the kidney of bile duct ligated rats. Forty Sprague-Dawley rats, each weighing 125 to 140 g, were included in the study. Extent of histological glomerular injury scores (GIS), arterial injury scores (AIS), and tubulointerstitial injury scores (TIS) in each animal were graded. Alpha-smooth muscle actin (alpha-SMA), tenascin, lectin (Ulex europaeus agglutinin-1), and vimentin were used to determine extent of the injury. The cholestasis was evidenced by a significant increase in the levels of serum total bilirubin in BDL rats (p < 0.01). Malondialdeyde MDA levels increased by the bile duct ligation (BDL) to 12.10 +/- 0.45. This value was significantly higher than the other groups (p < 0.01). Changes in the BDL kidney were marked at 7 days after surgery. GIS were observed to have the highest score, especially at juxtamedullary region in BDL/L-NAME rats, and AIS were also the highest score in this region. These observations were lower in BDL/MOL rats. There is a correlation between GIS and AIS scores (r = .2, p < .01). TIS revealed that BDL/L-NAME rats were significantly more damage than rats in the other groups (p<.001). MOL-treated rats showed considerably fewer lesions in the tubules and interstitium (p < .001). The tubular injuries observed in BDL and BDL/L-NAME rats were significantly attenuated by MOL treatment. Lectin was more and extensively stained in tubular epithelia of the BDL/L-NAME group than in the other (p <.05). Expression of tenascin in tubular epithelia was significantly higher in BDL and BDL/L-NAME as compared with controls (p < .01). Fibrous tissue was only observed in the BDL and BDL/L-NAME group. These areas were weakly stained with vimentin. alpha-SMA staining was more reduced in the L-NAME-treated arterioles than in BDL/MOL (p < .05). In conclusion, the analysis of cell injury based on a histological grading system in the model of BDL kidney allows the quantification of the degree of injury.     

Alteration in the fluorescence polarization of rat plasma and liver cell membranes following bile duct ligation in rats

The fluorescence polarization levels of liver cell membranes and plasma were analyzed to determine membrane fluidity following bile duct ligation (BDL) in rats. Fluorescence polarization was measured with a spectrofluorophotometer equipped with polarizers, using 1,6-diphenyl-1,3,5-hexatrien (DPH) as a probe. After bile duct ligation, liver cell membrane fluidity decreased significantly for up to 14 days after surgery (P<0.001 on 3rd and 7th days). The polarization of the plasma in rats with BDL slightly but significantly increased compared to the levels in the control animals over the 14-day period following BDL. In addition, a small but significant correlation in the polarization levels between plasma and liver cell membranes (r=0.362, P<0.02) was observed. The co-incubation of BDL plasma with normal liver cell membranes resulted in a decrease in membrane fluidity, which suggested that BDL rat plasma had a direct effect on membrane fluidity. After a 70% hepatectomy, the polarization of the membranes from remnant livers in the BDL rats remained elevated relative to the shamoperated controls. It is thus concluded that the membrane fluidity of the livers in BDL rats decreases following bile duct ligation and does not increase after a 70% hepatectomy, presumably due to the increased plasma level of bilirubin.     

Protection of the hypertrophied myocardium by crystalloid cardioplegia.

Patients with left ventricular hypertrophy (LVH) have a worse outcome after cardiac surgery than those without hypertrophy. We studied protection of hearts with LVH in an isolated rat heart model using multidose, cold, oxygenated cardioplegia. LVH was produced by banding the abdominal aorta in young rats. Six weeks after banding, this produced a 31% increase in the left ventricular dry weight/body weight ratio compared to two age-matched control groups comprising sham-operated and nonoperated animals. The recovery of cardiac output after arrest was higher in LVH (82 +/- 4% of prearrest) than in sham-operated (69 +/- 4%) or nonoperated (66 +/- 3%) control groups. The improved functional recovery in LVH occurred although there were no differences among the groups in myocardial adenosine triphosphate (ATP) and phosphocreatine (PCr) prior to arrest, at the end of arrest, or after reperfusion. Glycogen levels were also similar among the three groups prior to arrest and after reperfusion but were highest in LVH after arrest. Myocardial oxygen consumption (MVO2) and efficiency, expressed as cardiac output/MVO2, were similar among the groups prior to arrest. Myocardial efficiency after reperfusion declined in all groups but was best preserved in LVH. We also compared the sensitivity of hypertrophied and control hearts to the deleterious effects of calcium in cardioplegia. Calcium in the cardioplegia increased myocardial lactate production during arrest in a dose-related fashion and depressed myocardial levels of ATP, PCr, and glycogen at end arrest in all groups. Cardiac output recovery was also depressed by calcium but was still best in LVH. We conclude that the hypertrophied myocardium is well protected by standard cardioplegia and that calcium in cardioplegia does not preferentially depress recovery in LVH.     

Effects of the nitric oxide donor molsidomine on the early stages of liver damage in rats with bile duct ligation: a biochemical and immunohistochemical approach

This study aimed to evaluate the effects of the nitric oxide donor molsidomine on the early stages of liver damage and biochemical changes in rats with bile duct ligation (BDL). Forty prepubertal male Sprague-Dawley rats weighing 125-140 g were studied. Group 1 rats (sham-control, n = 10) were not subjected to any surgical manipulation. Group 2 rats (BDL/untreated, n = 10) were subjected to BDL but no drug was administered. Group 3 rats (BDL/L-NAME, n = 10) received a daily dose of N(G)-nitro-L-arginine methyl ester (L-NAME) intraperitoneally for 7 days after BDL. Group 4 rats (BDL/molsidomine, n = 10) received a daily dose of molsidomine by gastric tube for 7 days after BDL. After 1 week, biochemical and histological evaluations were performed and the liver hydroxyproline content was measured. Serum bilirubin and liver enzymes were significantly increased in the BDL/untreated, BDL/L-NAME and BDL/molsidomine groups in comparison with the sham-control group 1 week after BDL. However, the liver enzymes were significantly decreased in the BDL/molsidomine group in comparison with the BDL/untreated and BDL/L-NAME groups. In the BDL/L-NAME group, proliferation of portal and periportal biliary ductules with disorganization of the hepatocyte plates, dilated portal spaces and areas of polymorphonuclear leukocyte infiltration, fibrosis and hepatocyte necrosis were observed. In the BDL/molsidomine group, polymorphonuclear leukocyte infiltration, hepatocyte necrosis and fibrosis were rarely seen. The hydroxyproline content in the liver was increased 1 week after obstruction in the BDL/untreated and BDL/L-NAME groups when compared to BDL/molsidomine group. Collagen type-IV expression was not observed in the BDL/molsidomine group in contrast to the BDL/untreated and BDL/L-NAME groups. In conclusion, during 1 week of treatment, the nitric oxide donor molsidomine improved hepatic fibrosis in the hepatic parenchyma and did not affect serum bilirubin values, but positively affected the serum aspartate aminotransferase and alanine aminotransferase values.     

急性坏死性胰腺炎大鼠脑脊液髓磷脂碱性蛋白水平变化的初步研究

目的:研究急性坏死性胰腺炎(ANP)大鼠24h内脑脊液髓磷脂碱性蛋白(MBP)水平的动态变化。方法:应用5%和1%的牛磺胆酸钠分别诱导ANP和急性水肿性胰腺炎(AEP)大鼠模型,同时设立假手术对照组。分别于模型诱发后3、6、9、12及24h,经大鼠小脑延髓池抽取脑脊液。以酶联免疫吸附(ELISA)法测定标本中的MBP含量。结果:诱发ANP后3h,脑脊液MBP水平明显高于AEP组和假手术组(P<0.01);6h和9h时仍维持于较高水平(P<0.05),12h开始缓慢降低。而AEP组和假手术组的MBP水平无明显变化,在24h内维持于较低水平。结论:ANP大鼠早期时脑脊液MBP水平已异常升高,提示脑组织髓鞘结构已有损害。检测脑脊液MBP水平变化对临床胰腺炎病人并发脑功能障碍的诊断和预后评估具有重要意义。     

Sleeve Gastrectomy and Gastric Plication in the Rat Result in Weight Loss with Different Endocrine Profiles

Background

Restrictive bariatric surgery procedures currently used include adjustable gastric banding, sleeve gastrectomy (SG), and gastric plication (GP), of which the last two techniques still lack sufficient data and long-term studies on weight loss, surgical complications, resolution of comorbidities, and mechanisms of weight loss. Therefore, gastric plication and sleeve gastrectomy as a standalone procedure are still considered experimental. Our aim was to analyze the effects of SG and GP on body weight, food intake, and endocrine profile.

Methods

Forty-four male Wistar rats were randomized into six weight-matched groups and submitted either to SG, GP, or sham-operated. Sham-operated rats were divided into pair-fed and fed ad libitum controls, one for each procedure. Animals were followed up for 21 days after surgery, while body weight and food intake were recorded daily, when fasting ghrelin, leptin, insulin and glucose plasma levels, and ghrelin expression in the stomach were measured.

Results

Rats submitted to SG and GP showed a significant decrease in body weight gain to the same extent as rats pair-fed to the surgical groups when compared to sham-operated fed ad libitum controls. After surgery, SG rats showed no difference in body composition, ghrelin, leptin, insulin, or glucose levels, while GP rats displayed lower body fat content and leptin levels compared to controls. Ghrelin was also lower in GP rats compared to sham-operated pair-fed rats. Ghrelin expression displayed a pattern similar to circulating ghrelin.

Conclusions

SG and GP result in weight loss, although with differences in body composition and metabolic and endocrine profiles.     

Ovariectomy in the rat induces a rapid increase in the urinary excretion of hydroxylysine glycosides and non-reducible crosslink residues

The ovariectomized rat is the most commonly used animal model of human postmenopausal osteoporosis, exhibiting a high rate of bone turnover with resorption exceeding formation. At present, bone turnover is quantified directly by dynamic histomorphometry. The aim of the present study was to determine whether the measurement of the urinary output of some specific bone collagen catabolites — pyridinolines and hydroxylysine glycosides — could be used to indirectly monitor the initial phase of bone turnover increase in ovariectomized 90-day-old rats. Ninety-day-old female rats were randomly divided into three groups (n=6): ovariectomized, sham-operated and non-treated controls. Urine samples (24 h) were collected 6 days before surgery and twice weekly for the 4 weeks following ovariectomy. Urinary excretion of pyridinoline (PYD), deoxypyridinoline (DPD), glucosyl-galactosyl-hydroxylysine (GGHYL) and galactosyl-hydroxylysine (GHYL) were measured. As expected, ovariectomy was associated with a significant decrease in bone mineral density in both the proximal tibial and distal femoral metaphysis. Compared with both sham-operated and control animals, ovariectomized rats showed significant increases in PYD, GGHYL and GHYL urinary output 8 days after surgery and in DPD output after 15 days. These changes were maintained throughout the study. The results confirm that measurement of the urinary excretion of pyridinolines and hydroxylysine glycosides represents a powerful tool for detecting the onset of bone turnover in ovariectomized 90-day-old rats.     

Renal vascular reactivity in jaundice

Obstructive jaundice is associated with a predisposition to hypotension and acute renal failure that may be related to changes in renovascular responsiveness, particularly to norepinephrine (NE). This study was undertaken to investigate changes in vascular response to NE and to determine how these changes are related to prostaglandins. Kidneys from bile duct-ligated (BDL) rabbits (n = 5) were perfused with Krebs' solution at 7.65 ml/min, and the response to varying boluses of NE (0.78 to 6.24 micrograms) was measured as changes in perfusion pressure. When compared with sham-operated control kidneys (n = 8), a significantly blunted response was seen at all doses tested. The NE response was further assessed by measuring force development in mounted segments of main renal arteries (MRAs) (n = 8) and interlobar arteries (ILAs) (n = 6) from BDL rabbits and sham-operated controls (MRA, n = 8; ILA, n = 6). The dose-response curves were significantly depressed in both MRAs and ILAs from BDL animals. In addition, MRAs from sham-operated control animals exhibited decreased response to NE after incubation for 1 hour in jaundiced serum. This attenuated response of MRAs to NE was prevented when indomethacin (5 mg/kg) was given to BDL rabbits before death (n = 9) or when 10(-6)mol/L of indomethacin was added to jaundiced serum during incubation (n = 6). These results indicate that obstructive jaundice induces a decreased vascular contractile response in rabbits to NE and that this effect is mediated by prostaglandins.     

Treatment of Children with Steroid Refractory Idiopathic Nephrotic Syndrome: The Kuwaiti Experience

The aim of this study is to evaluate histopathological findings induced by N^Ω‐nitro‐L‐arginine methyl ester (L‐NAME) and molsidomine (MOL) on the kidney of bile duct ligated rats. Forty Sprague–Dawley rats, each weighing 125 to 140 g, were included in the study. Extent of histological glomerular injury scores (GIS), arterial injury scores (AIS), and tubulointerstitial injury scores (TIS) in each animal were graded. Alpha‐smooth muscle actin (α‐SMA), tenascin, lectin (Ulex europaeus agglutinin‐1), and vimentin were used to determine extent of the injury. The cholestasis was evidenced by a significant increase in the levels of serum total bilirubin in BDL rats (p < 0.01). Malondialdeyde MDA levels increased by the bile duct ligation (BDL) to 12.10 ± 0.45. This value was significantly higher than the other groups (p < 0.01). Changes in the BDL kidney were marked at 7 days after surgery. GIS were observed to have the highest score, especially at juxtamedullary region in BDL/L‐NAME rats, and AIS were also the highest score in this region. These observations were lower in BDL/MOL rats. There is a correlation between GIS and AIS scores (r = .2, p < .01). TIS revealed that BDL/L‐NAME rats were significantly more damage than rats in the other groups (p < .001). MOL‐treated rats showed considerably fewer lesions in the tubules and interstitium (p < .001). The tubular injuries observed in BDL and BDL/L‐NAME rats were significantly attenuated by MOL treatment. Lectin was more and extensively stained in tubular epithelia of the BDL/L‐NAME group than in the other (p < .05). Expression of tenascin in tubular epithelia was significantly higher in BDL and BDL/L‐NAME as compared with controls (p < .01). Fibrous tissue was only observed in the BDL and BDL/L‐NAME group. These areas were weakly stained with vimentin. α‐SMA staining was more reduced in the L‐NAME‐treated arterioles than in BDL/MOL (p < .05). In conclusion, the analysis of cell injury based on a histological grading system in the model of BDL kidney allows the quantification of the degree of injury.     

The influence of inhalational anesthetics on in vivo and in vitro benzodiazepine receptor binding in the rat cerebral cortex.

The effect of volatile anesthetics on benzodiazepine receptor binding was examined autoradiographically in the rat brain both in vivo and in vitro with the use of [3H]-Ro-15-1788, a benzodiazepine antagonist. For in vitro studies, slide-mounted brain sections were incubated at 37 degrees C in Tris buffer (50 mM, pH 7.4) with [3H]-Ro-15-1788 (flumazenil, 0.5-12.0 nM) in the presence of air (control) or 1 MAC concentrations of halothane or isoflurane. Brain sections were exposed to x-ray film and their images digitized, and specific cortical [3H]-Ro-15-1788 binding was determined. A Scatchard plot of specific cortical binding was constructed, and the dissociation constant (KD) and maximum bound ligand per milligram tissue (Bmax) were determined for each experimental group. In the in vivo trials, rats were anesthetized with 1 MAC halothane or isoflurane; 0.5 microCi/g [3H]-Ro-15-1788 was given intravenously, and the animals were killed 15 min later. Seven standardized sagittal brain sections were examined from autoradiographs. Mean specific cortical binding was determined for each group and was compared with binding in unanesthetized control rats. A third experimental trial analyzed the timed arterial blood history of [3H]-Ro-15-1788 in animals prepared exactly as in the in vivo study. The [3H]-Ro-15-1788 blood clearance over 20 min and plasma [3H]-Ro-15-1788 levels at 15 min after injection of isotope were evaluated. In vitro Scatchard analysis showed no difference in experimental groups in KD or Bmax at 37 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)     

Rat renal function four days after bile-duct ligation: effects of indomethacin and vasoactive agents

The purpose of this study was to assess the effects of the cyclooxygenase inhibitor, indomethacin, and some vasoactive agents on the renal functional parameters during the early liver injury induced by four days bile duct ligation (BDL). Wistar rats with four days-BDL and control-sham operated were used. Renal function was measured in anesthetized rat treated with a single dose of indomethacin (control, 0.3, 1.0, 3.0 mg/kg b.w.; i.v.) one hour before clearance studies. Sulindac effects were also evaluated (5 mg/kg b.w., i.p). Isolated rat kidney preparations from control and BDL donor rats were used to study renal vascular response to noradrenaline, carbachol or sodium nitroprusside. The bile duct ligation promoted a diminished renal cortical plasma flow (RCPF) on the fourth day post surgery accompanied with a diminution in the glomerular filtration rate (GFR), increased filtration fraction and increased fractional excretion of water and sodium. Indomethacin 0.3 mg/kg induced an increase in GFR and RCPF, maintaining the high filtration fraction in BDL rats. The other doses did not alter these parameters as compared with bile duct ligated rats without treatment, but indomethacin 3 mg/kg caused a significant increase in filtration fraction. Indomethacin induced dose-dependent diminution in natriuresis in sham and BDL groups. Sulindac did not modify hemodynamic parameters, but induced antinatriuresis and antidiuresis in both experimental groups. Maximal vascular responses to noradrenaline measured in isolated rat kidneys were statistically diminished in BDL-rats as compared with controls (C, n=7; 35.0+/-2.3 mmHg ml(-1) min; BDL-rats, n=5; 23.8+/-0.7 mmHg ml(-1) min; p<0.02), without changes in EC15. Maximal relaxation induced by sodium nitroprusside in the phenylephrine (PHE)-pre-constricted renal vasculature in control preparations did not differ from that observed in BDL group (C: n=6; 49.5+/-2.3%). Values of EC50 were 1.26+/-0.07 microM (n=6) in control preparations and 0.34+/-0.03 microM (n=4) in kidneys from BDL-rats (p<0.001). Carbachol induced a biphasic relaxation of PHE-pre-constricted renal vasculature. No differences in maximal responses were found. EC50 value of the second phase in BDL group was significantly decreased compared to control preparations (C: n=6, 0.47+/-0.05 microM; BDL: n=6, 0.22+/-0.03 microM p<0.001). The present results show that the altered renal function after a short time post bile duct ligation is determined, at least in part, by increased release of arachidonic derivatives in vascular bed and tubular cells. At this stage of liver injury, the alteration in the renal vascular response to different vasoactive agents is remarkable.     

Early Improvement of Glucose Tolerance after Ileal Transposition in a Non-obese Type 2 Diabetes Rat Model

Background: Surgical operations which shorten the intestinal tract between the stomach and the terminal ileum result in an early improvement in type 2 diabetes, and one possible explanation is the arrival of undigested food in the terminal ileum. This study was designed to evaluate the role of the distal ileum in the improvement of glucose control in type 2 diabetic patients who underwent bariatric surgery. Methods: An ileal transposition (IT) to the jejunum was performed in lean diabetic Goto-Kakizaki (GK) rats. The IT was compared to sham-operated diabetic rats and a control group of diabetic rats. Non-diabetic controls were age-matched Sprague-Dawley (SD) rats, which underwent IT and no operation. Food intake and body weight were measured. An oral glucose tolerance test (OGTT) was performed 10 days before the operation and 10 days, 30 days and 45 days after the surgery. GLP-1 and insulin were measured during the OGTT 45 days after surgery. An insulin tolerance test (ITT) was performed 50 days after surgery. Results: Glucose tolerance improved in the IT diabetic group compared with both the sham-operated animals and control diabetic group 30 days and 45 days after surgery (P=0.029 and P=0.023, respectively). Insulin sensitivity, as measured by an ITT, was not significantly different between diabetic groups and the normal groups respectively after surgery. No differences in basal glucose and glucose tolerance were noted between non-diabetic operated animals and control non-diabetic rats. No differences were recorded between the diabetic rat groups and the non-diabetic rats in terms of weight and food intake. GLP-1 levels were significantly higher in the IT diabetic group compared with the sham-operated rats (P=0.05). Conclusions: Ileal transposition is effective in inducing an improvement in glucose tolerance in lean diabetic rats without affecting weight and food intake. The possible mechanism underlying the early improvement of diabetes after bariatric surgery may be due to the action of the terminal ileum through an insulin-independent action.     

Intestinal Endotoxins as Co-Factors of Liver Injury in Obstructive Jaundice

The concept of endotoxin-mediated rather than direct liver injury in biliary obsruction was investigated using the experimental rat model of bile duct ligation (BDL) and small bowel bacterial overgrowth (SBBO). Small identical doses of intravenous endotoxin (bacterial LPS) caused a significantly more severe liver injury in rats with BDL, compared with sham-operated rats, suggesting the possible contribution of LPS in this type of liver damage. BDL was then combined with surgically created jejunal self-filling blind loops, which resulted in SBBO. Plasma LPS level increased significantly, and once again a more severe liver injury, determined by liver histology and serum gamma-glutamyl transpeptidase levels, was observed compared with the control group of rats with BDL+self-emptying blind loops. The data presented suggest that small amounts of exogenous LPS and/or the ordinarily innocous amounts of LPS constantly absorbed from the intestinal tract may be critical in the hepatic damage caused by obstruction of the biliary tract.     

Structural analysis of meniscal allografts after immediate and delayed transplantation in rabbits

Purpose: To compare long-term performance of meniscal allografts transplanted immediately after meniscectomy and allografts transplanted 6 weeks after meniscectomy. Type of Study: Experimental study. Methods: Twenty-one rabbits were subjected to meniscectomy and divided into 3 groups of 7 animals. Immediate meniscal transplantation was performed in group A (6-week follow-up) and group B (1-year follow-up). Group C underwent delayed transplantation 6 weeks after meniscectomy. One animal in group B developed infective arthritis and was not included. Six nonoperated knees served as controls. Four other knees were subjected to a sham procedure. Menisci were examined macroscopically and histologically at 6 weeks (group A and 2 sham- operated animals) and 1 year (group B, C, controls, and 2 sham-operated animals). Results: Capsular ingrowth was observed in all allografts. At 1 year, osteoarthritic changes in the delayed transplant group were more pronounced than in the immediate transplant group. Menisci in nonoperated controls and sham-operated knees appeared normal. No differences in shrinkage of allografts were observed between groups A and B. Group C showed significantly more shrinkage than allografts in both group A (P = .004) and group B (P = .005). Two allografts in group C were completely degenerated. Differences in architecture of the allografts were not found between groups A, B, and C. In both the peripheral and central areas of transplanted menisci, the number of cells was frequently increased because of repopulation even at 6-week follow-up. Conclusions: Delayed meniscal allograft transplantation causes distinct structural damage to menisci in comparison with immediate transplantation.