Effects of Combined Pulse Electromagnetic Field Stimulation Plus Glutamine on the Healing of Colonic Anastomosis in Rats

Purpose An experimental study was designed to investigate the effect of combined pulse electromagnetic field (PEMF) stimulation plus glutamine administration on colonic anastomosis. Methods Anastomosis of the left colon was performed in 28 rats, which were divided into four groups; Group 1: normal resection anastomosis plus oral 50 mg/kg/day glutamine; Group 2: normal resection anastomosis plus PEMF stimulation plus oral 50 mg/kg/day glutamine; Group 3: normal resection anastomosis plus PEMF stimulation; Group 4: normal resection anastomosis. On the seventh postoperative day, the animals were killed and the bursting pressure and tissue hydroxyproline concentration of the anastomosis were analyzed and compared. Results The mean anastomotic bursting pressure in Group 2 was significantly higher than in Groups 1 and 4. On the other hand, the mean anastomotic bursting pressure in Group 1 was significantly higher than in Group 4. The collagen deposition and the fibroblast infiltration were significantly increased on the seventh day in Group 3 compared the other groups. On the other hand, Groups 1 and 2 had higher scores for collagen deposition and fibroblast infiltration than Group 4. Conclusions In conclusion, burst pressures, hydroxyproline, and histologic features (fibroblast infiltration and collagen deposition) were improved in the PEMF group, and both PEMF and glutamine-enriched nutrition provide a significant gain in the strength of colonic anastomoses in rats.     

Colonic Electrical Stimulation Regulates Colonic Transit Via the Nitrergic Pathway in Rats

Gastrointestinal electrical stimulation has been proposed for the treatment of gastrointestinal motor disorders. However, little is known about potential roles of colonic electrical stimulation (CES). The aim of this study was to evaluate the effect and mechanism of CES on colonic transit in conscious rats. Male rats (N = 14) were equipped with a pair of colonic serosal electrodes for stimulation and a catheter in the colon. Colonic transit was assessed in four randomized sessions with or without CES and with or without nitric oxide synthesis blocker, L-NNA, by calculating the output of phenol red from the anus every 10 min for 90 min. Results were as follows. (1) CES with trains of short pulses significantly enhanced colonic transit. Colonic emptying was 57.3 ± 6.1% in the control session and 81.9 ± 4.6% with CES at 90 min, reflecting a 43% increase. (2) L-NNA delayed colonic transit compared with saline and prevented the accelerative effect of CES on colonic transit. We conclude that CES has an excitatory effect on colonic transit and this excitatory effect may be mediated via the nitrergic pathway.     

The Effect of Capecitabine on the Healing of Colonic Anastomoses in Rats

Purpose Capecitabine is a fluoropyrimidine carbamate with antineoplasmatic activity, recommended for the treatment of colorectal cancer. This study was designed to assess the effectiveness of the perioperative administration of capecitabine on the healing process of colonic anastomosis. Methods Sixty Wistar rats were used, which were randomized in 2 groups of 30 each. The study group was subjected to colonic anastomosis and treated with therapeutic doses of capecitabine (359 mg/kg, or 2/3 of the mean toxic dose) by mouth one week before anastomosis and throughout the study. The control group received only placebo medication. Both groups were further divided into three subgroups, each of ten animals. In both study and control groups, ten animals were killed in each session on postoperative Days 3, 7, and 14. Results We found no negative impact on the healing of colonic anastomosis on capecitabine administration. The rate of anastomotic leakage and septic complications were not found to be significantly different between the study and control groups. The median bursting pressure was found to be significantly higher in the study subgroup killed on the third day (68 vs. 46 mmHg of the control group). Conclusions Perioperative administration of capecitabine does not have a negative impact on colonic anastomosis in rats. Presented at the International Congress on Colorectal Cancer, Chalkidiki, Greece, May 28 to 31, 2004. Presented at the Congress of Northern Greece Surgical Association, Alexandroupoli, Greece, October 14 to 15, 2005. Supported by the Procurement of Capecitabine, F. Hoffman La-Roche, Basle, Switzerland. Reprints are not available.     

Anti-Stress Effects of Transcutaneous Electrical Nerve Stimulation (TENS) on Colonic Motility in Rats

Background  

Disorders of colonic motility may contribute to symptoms in patients with irritable bowel syndrome (IBS), and stress is widely believed to play a major role in developing IBS. Stress increases corticotropin releasing factor (CRF) of the hypothalamus, resulting in acceleration of colonic transit in rodents. In contrast, hypothalamic oxytocin (OXT) has an anti-stress effect via inhibiting CRF expression and hypothalamic–pituitary–adrenal axis activity. Although transcutaneous electrical nerve stimulation (TENS) and acupuncture have been shown to have anti-stress effects, the mechanism of the beneficial effects remains unknown.     

The Effect of Octreotide on Healing of Injured Colonic Anastomosis with Immediate Postoperative Intraperitoneal Administration of 5-Fluorouracil

Purpose This study was designed to investigate the effect of octreotide on side effects of immediate usage of 5-fluorouracil after colonic anastomosis. Methods Forty male Wistar rats were randomly assigned into four groups and underwent standardized left colonic anastomosis. The rats served as control or received intraperitoneal 5-fluorouracil (20 mg/kg daily), subcutaneous octreotide (20 μg/kg daily), or both. Diarrhea and wound complications were noted during the experiment. The colonic anastomoses were assessed for healing on postoperative Day 7 by determining the anastomotic bursting pressure, performing histologic examination, and measuring the tissue hydroxyproline content, serum malondialdehyde, and nitric oxide levels. Intraperitoneal adhesions and anastomotic leakage were also noted. Results No statistical significant difference was found between the control and octreotide groups for each of the parameters measured. Immediate 5-fluorouracil use resulted with higher adhesion score (P = 0.002), significant depression in anastomotic bursting pressure (P = 0.0001), histopathologic score (P = 0.0001), hydroxyproline content (P = 0.0001), and increasing nitric oxide (P = 0.0001) and malondialdehyde levels (P = 0.0001) compared with the control group. Diarrhea was seen in 80 percent of the 5-fluorouracil group but in neither the control nor octreotide groups (P = 0.0001 for each comparison). However, all these parameters were ameliorated by use of concomitant octreotide and 5-fluorouracil (P = 0.019, P = 0.023, P = 0.0001, P = 0.006, P = 0.0001, and P = 0.013, respectively). In addition, diarrhea was found to be prevented (P = 0.0001). Conclusions The results of this study showed that concomitant octreotide use might prevent the side effects of 5-fluorouracil, such as diarrhea, postoperative adhesion, and delaying the anastomotic healing parameters. In addition, it might reduce tissue damage and inflammation.     

The Effect of Insulin-Like Growth Factor I on Healing of Colonic Anastomoses in Cortisone-Treated Rats

Purpose This study was designed to investigate whether intraperitoneally injected insulin-like growth factor I is able to protect colonic healing from the adverse effects of hydrocortisone therapy. Methods Eighty female Wistar rats were randomized into four groups (20 rats each). After resection of a segment of transverse colon, an end-to-end anastomosis was performed. Hydrocortisone (5 mg/kg body weight) was injected intramuscularly in rats of cortisone (Group B) and insulin-like growth factor I + cortisone (Group D) groups once daily for seven days before and after the operation. Insulin-like growth factor I (2 mg/kg body weight) was intraperitoneally injected in rats of the insulin-like growth factor I (Group C) and the insulin-like growth factor I + Cortisone (Group D) groups immediately after operation and on the second, fourth, and sixth postoperative days. Rats were killed on the seventh postoperative day. Anastomoses were graded macroscopically and histologically, and bursting pressures and anastomotic hydroxyproline levels were recorded. Statistical analyses were performed by using Fisher's exact test for the comparison of proportions and ANOVA for the comparison of means among groups with subsequent post-hoc analysis using Bonferroni correction. Results Leakage rate was significantly higher in the cortisone (Group B) group. Bursting pressures were significantly lower in the cortisone group, whereas they were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups (Group C and D). Histology revealed a significant decrease of inflammatory cell infiltration, neoangiogenesis, and fibroblast activity in the cortisone group compared with the control group, whereas these parameters were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups. Hydroxyproline levels were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups. Conclusions Hydrocortisone inhibits the healing of colonic anastomoses. However, insulin-like growth factor I given intraperitoneally mediates the deleterious effects of cortisone and protects colonic healing in rats.     

Electroacupuncture Elicits Dual Effects: Stimulation of Delayed Gastric Emptying and Inhibition of Accelerated Colonic Transit Induced by Restraint Stress in Rats

Acupuncture has been used for treating functional gastrointestinal (GI) disorders. Animal studies have demonstrated that acupuncture antagonized various stress-induced responses. We investigated the effects of electroacupuncture (EA) at ST-36 (Zusanli; lower limb) on stress-induced alteration of GI motor activities. Solid gastric emptying was significantly delayed by restraint stress (29.6±2.4%; n=7) compared to that of controls (60.0±2.5%; n=8). Delayed gastric emptying was significantly improved by EA at ST-36 (47.2±1.8%). Intracisternal (IC) injection of corticotropin releasing factor (CRF; 1 μg) delayed gastric emptying to 25.4±3.1%, which was also improved by EA at ST-36, to 53.0±7.1% (n=8). The stimulatory effect of EA on stress-induced delayed gastric emptying was abolished by atropine (17.6±1.9%) but not by guanethidine (42.2±2.3%). Colonic transit was significantly accelerated by restraint stress (GC=7.2±0.3; n=8) compared to that of controls (GC=5.2±0.2; n=8). Accelerated colonic transit was significantly reduced by EA at ST-36 (GC=4.9±0.3). IC injection of CRF accelerated colonic transit (GC=6.9±0.2), which was also normalized by EA at ST-36 (GC=4.7±0.2). The inhibitory effect of EA on stress-induced acceleration of colonic transit was not affected by guanethidine (GC=4.6±0.3). In conclusion, EA at ST-36 showed dual effects: stimulation of stress-induced delayed gastric emptying and inhibition of stress-induced acceleration of colonic transit. The stimulatory effect of EA on stress-induced delayed gastric emptying is mediated via cholinergic pathways. The inhibitory effect of EA on stress-induced acceleration of colonic transit is independent of the sympathetic pathway.     

Improvement of Colonic Healing by Preoperative Rectal Irrigation With Short-Chain Fatty Acids in Rats Given Radiotherapy

BACKGROUND We investigated the effect of preoperative rectal irrigation with short-chain fatty acids on irradiated colonic anastomosis in rats.METHODS Sixty male Wistar rats were divided into four groups. Group I (control group, n = 15) underwent left colon resection and primary anastomosis. Group II (Short-chain fatty acids pretreatment group, n = 15) had short-chain fatty acids rectal irrigation for five days preoperatively. Group III (preoperative radiotherapy group, n = 15) underwent irradiation to the whole pelvis eight and four days before the operation, for a total dose of 20 Gy. Group IV (preoperative radiotherapy group + short-chain fatty acids pretreatment group, n = 15) had rectal irrigation with short-chain fatty acids for five days after the second irradiation. Within each group, animals were anesthetized to assess the clinical, mechanical, histologic, and biochemical parameters of anastomotic healing on either the third or seventh postoperative days.RESULTS The mean bursting pressure was significantly low in Group III on Day 3 and was significantly high in Group IV on Day 7 (P = 0.001, P = 0.021). The burst occurred at the anastomoses in all animals tested on the third postoperative day, and outside of the anastomoses in all animals tested on the seventh postoperative day. The histologic parameters of anastomotic healing, such as epithelial regeneration and formation of granulation tissue, were significantly improved by use of preoperative rectal irrigation with short-chain fatty acids on Day 7. The amount of total and salt-soluble collagen concentrations significantly increased in Group IV compared with the control group on Day 3 (P = 0.008, P = 0.004).CONCLUSION Some mechanical and histologic aspects of colonic anastomotic healing can be adversely affected by preoperative radiotherapy, but rectal irrigation with short-chain fatty acids may improve anastomotic healing.Supported by The Turkish Surgical Society, as funded by a grant from the Sanofi Pharma.     

Effects of Perorally Applied Endotoxin on Colonic Mucins of Germfree Rats

Background: The intestinal epithelium, with the potential to restrict luminal noxae from the host, secretes a mucous layer with various protective functions. Microbial colonization of germfree (GF) rats stimulates this mucin-secreting tissue. The present study determined the effect of bacterial lipopolysaccharides (LPS) on this process. Methods: One, 3, and 5 days after peroral application of 35 μg LPS/100 g body weight (from Escherichia coli O55:B5), LPS concentrations were monitored in ingesta, intestinal tissue, and liver. Mucin high molecular weight glycoproteins (HMG), released in response to LPS, were isolated and separated into mucins, i) attached to the colonic epithelium (EM) and ii) mixed to the luminal content (LM), respectively. Subsequently, the binding capacity of both mucin fractions for various lectins and for type-1 pili expressing E. coli was determined. Results: Ingesta and tissue had maximal LPS concentrations on days 3 (jejunum) and 5 (colon). Maximal EM secretion was found on day 3, release of LM further increased to day 5. Both mucin fractions had altered glycosylation patterns: augmentation of β-galactose, α-N-acetyl galactosamine, and mannose coincided with a decrease in α-fucose. Compared with the controls, attachment of E. coli to EM increased slightly on day 1 only; the binding capacity of LM increased continuously up to day 5. Conclusion: Results suggest that mucins, released in response to LPS, in addition to the epithelial protection, support the gut microbial clearance system.     

Effects of Prenatal Exposure to Alcohol Plus Caffeine in Rats: Pregnancy Outcome and Early Offspring Development

The factors determining susceptibility to fetal alcohol syndrome (FAS) are not fully understood. We used an animal model of alcohol-related birth defects to assess the coteratogenic potential of caffeine as a risk factor in FAS. Rats were exposed prenatally to alcohol (˜15 g/kg/day) with or without caffeine (˜84 mg/kg/day) from gestation days 6 through 20 via liquid diet. All control groups were pair-fed to the alcohol-exposed groups. In addition, some controls had free access to lab chow and water. Prenatal exposure to alcohol or caffeine reduced both maternal weight gain during pregnancy and birth-weight of offspring. The combination of alcohol plus caffeine produced an additive effect in reducing birthweight and synergistic effects in increasing postnatal offspring mortality. Prenatal alcohol exposure had a significant negative impact on several developmental indices, including grip strength and negative geotaxis. Prenatal caffeine exposure did not affect maturational measures and did reduce offspring serum levels of the zinc-dependent enzyme alkaline phosphatase. This study in rats demonstrated that caffeine can exacerbate some of the effects of alcohol on prenatal development, specifically reduced birthweight, litter size, and postnatal survival, but that caffeine does not appear to alter prenatal alcohol-induced delays in early postnatal maturation of survivors. The relative impact of intralitter birthweight rank on developmental outcome was also assessed. Birthweight influenced development, but did not interact significantly with either prenatal alcohol or caffeine. The results imply that high levels of maternal caffeine intake in humans could increase the likelihood that a child exposed prenatally to alcohol would be born with significantly lowered birthweight, one of the cardinal diagnostic criteria for FAS.     

Inhibitory Effects and Mechanisms of Colonic Electric Stimulation on Gastric and Rectal Tone in Conscious Dogs

Purpose Colonic electric stimulation has been shown to alter motor functions of the colon; however, its effects on other organs of the gut have been investigated rarely. Methods This study was performed in 12 dogs implanted with one pair of colonic serosal electrodes and a gastric cannula. Experiments were performed to study: 1) the effect of colonic electric stimulation on proximal gastric tone and compliance; 2) the effect of colonic electric stimulation on rectal tone and compliance; 3) the sympathetic mechanism involved in the effects of colonic electric stimulation on gastric/rectal tone. A computerized barostat was used to assess gastric/rectal tone and compliance. Results Colonic electric stimulation inhibited both gastric and rectal tone with a higher potency in gastric tone. Colonic electric stimulation reduced gastric but not rectal compliance. The inhibitory effect of colonic electric stimulation on gastric tone but not rectal tone was abolished by an adrenergic blockade, guanethidine. Conclusions Colonic electric stimulation inhibits both gastric and rectal tone with a higher potency in inhibiting gastric tone. Colonic electric stimulation reduces gastric but not rectal compliance. The inhibitory effect of colonic electric stimulation on gastric tone seems to be mediated by the sympathetic pathway.     

The Effects of Intraperitoneal Sildenafil Administration on Healing of Left Colonic Anastomoses and Intra-Abdominal Adhesion Formation in the Presence of Intra-Abdominal Infection

Purpose

The objective of this pilot study was to establish an animal model for intra-abdominal infection and to examine the effect of sildenafil on anastomotic healing of the left colon and intra-abdominal adhesion formation.

Methods

Fourteen Winstar rats underwent colonic transsection and primary anastomosis after performing intra-abdominal infection. Rats were divided into two groups: Group 1 (n?=?7): intra-abdominal infection, resection, and anastomoses; Group 2 (n?=?7): intra-abdominal infection, resection, anastomoses, and sildenafil. Anastomotic bursting pressures, hydroxyproline levels, histopathologic grading, and abdominal adhesions were accessed on the postoperative Day 7.

Results

Anastomotic healing was found to be improved in terms of a bursting pressure (P?=?0.02). Histopathological examination revealed an increase in angiogenesis (P?=?0.007). Moreover, intra-abdominal adhesions were significantly less in rats given sildenafil (P?=?0.03).

Conclusion

Sildenafil may improve anastomotic healing of the left colon and diminishes peritoneal adhesion formation in the presense of abdominal infection.     

The Effect of Azathioprine on Anastomotic Healing: An Experimental Study in Rats

Purpose

The cytotoxic and immunosuppressive effects of azathioprine, which mitigate the disease activity in inflammatory bowel disease, may compromise the healing of intestinal anastomoses leading to an increased risk of anastomotic leakage. The effect of azathioprine treatment on intestinal healing was tested.

Methods

In an experimental study, rats were randomly given one oral dose of azathioprine (5 mg or 20 mg/kg body weight per day) or placebo. After 28 days of treatment, a left colonic anastomosis was performed. After three days of healing, the breaking strengths of the anastomoses were tested, along with measurements of azathioprine major metabolite concentrations: 6-thioguanine and 6-methyl-mercaptopurine.

Results

There were no significant differences in the anastomotic breaking strength between the three groups.

Conclusions

Daily treatment for four weeks with high or low azathioprine doses has no inhibitory effect on colonic healing in rats.

     

Development of a Chronic Colonic Intubation Model in Rats for the Study of Luminal Factors in Colonic Diseases

INTRODUCTION: A rat model of long-term colonic intubation has been developed to facilitate the in vivo study of colonic biology. This study aims to characterize this model. METHODS: The effects of intubation and sham surgery on animal behavior and weight gain were measured and compared with unoperated controls. The reproducibility of the model was assessed by comparing complication and failure rates for three operators. The distribution and excretion of infused materials were studied using radiology and gas chromatography of feces, respectively. The effects of the colonic tube and infusions on the mucosa were assessed histologically. RESULTS: There was about 10 percent weight loss postoperatively, more marked in those rats undergoing more extensive surgery. Subsequent weight gain was similar in all groups, and no behavioral effects of surgery were noted. There were no differences in histologic appearances or proliferative indices among the groups. All three operators had similar complication and tube dislodgement rates. Radiologic examination showed even distribution of infusate regardless of fecal consistency. Infusion through the two tubes allowed the cecum and the distal bowel to be targeted differentially. The infusions did not alter the consistency of the fecal pellets or induce defecation. Gas chromatography at various time points after butyrate infusion showed a small, but statistically insignificant, rise in fecal excretion, representing less than 10 percent of the infused butyrate. CONCLUSIONS: A highly reproducible in vivo rat model, with an experimental life span of five to six weeks, has been achieved. Biological agents can be accurately delivered via the colonic tubes and are retained in the colonic segment of interest. This intubation model should provide a valuable tool in the future for in vivo studies of colonic biology.     

The Effects of Combined Treatment of Antioxidants on the Liver Injury in STZ Diabetic Rats

The aim of this study was to examine whether an antioxidant combination of vitamin C, vitamin E, and sodium selenate (Se) has an effect on the liver of diabetic rats. Vitamin C, vitamin E, and Se were administered for 30 days to streptozotocin (STZ)-induced diabetic and control groups. In the STZ diabetic group, blood glucose levels, liver lipid peroxidation (LPO), and nonenzymatic glycosylation (NEG) levels increased, but blood and liver glutathione levels decreased. On the other hand, combined antioxidant treatment reversed these effects. In the diabetic group, some degenerative changes were observed by light and electron microscopic examinations, but the degenerative changes decreased in the diabetic group given antioxidant combination. Proliferating cell nuclear antigen (PCNA) immunohistochemistry showed that the number of proliferative hepatocytes increased significantly with antioxidant treatment. It was concluded that combined treatment with vitamin C, vitamin E, and Se has a curative effect against the hepatotoxicity produced by STZ-induced diabetes.     

Effect of Portacaval Anastomosis on Glutamine Synthetase Protein and Gene Expression in Brain, Liver and Skeletal Muscle

The effects of chronic liver insufficiency resulting from end-to-side portacaval anastomosis (PCA) on glutamine synthetase (GS) activities, protein and gene expression were studied in brain, liver and skeletal muscle of male adult rats. Four weeks following PCA, activities of GS in cerebral cortex and cerebellum were reduced by 32% and 37% (p<0.05) respectively whereas GS activities in muscle were increased by 52% (p<0.05). GS activities in liver were decreased by up to 90% (p<0.01), a finding which undoubtedly reflects the loss of GS-rich perivenous hepatocytes following portal-systemic shunting. Immunoblotting techniques revealed no change in GS protein content of brain regions or muscle but a significant loss in liver of PCA rats. GS mRNA determined by semi-quantitative RT-PCR was also significantly decreased in the livers of PCA rats compared to sham-operated controls. These findings demonstrate that PCA results in a loss of GS gene expression in the liver and that brain does not show a compensatory induction of enzyme activity, rendering it particularly sensitive to increases in ammonia in chronic liver failure. The finding of a post-translational increase of GS in muscle following portacaval shunting suggests that, in chronic liver failure, muscle becomes the major organ responsible for the removal of excess blood-borne ammonia.     

丹酚酸联合氨氯地平对高血压合并高脂血症大鼠模型心血管的影响

目的 观察丹酚酸与氨氯地平联合使用对高血压合并高脂血症大鼠模型的心血管效应.方法 取24只自发性高血压大鼠,高脂饲料饲喂2周后,造成高血压合并高脂血症大鼠模型,并根据血压、血脂、体重水平分成4组,即空白对照组、氨氯地平组、氨氯地平阿托伐他汀组和联合用药组,每组6只,连续给药4周,每周尾套法测血压,给药结束后测心脏血流动力学参数,取血浆测定BNP和NO、Ang-Ⅱ水平,并取心肌,测定组织中Ang-Ⅱ水平.结果 与空白对照组比较,各药物干预组均能显著降低血压、HR和LVEDP以及血浆和心肌组织中Ang-Ⅱ水平（P＜0.05,P＜0.01）,显著升高LVDP（P＜0.01）;同时,氨氯地平阿托伐他汀组和联合用药组均能明显升高LVSP和＋dp/dtmax（P＜0.05,P＜0.01）,降低血浆BNP水平（P＜0.05）,且联合用药组能明显升高-dp/dtmax和NO水平（P＜0.01）;另外,联合用药组的HR明显低于氨氯地平组和氨氯地平阿托伐他汀组（P＜0.05,P＜0.01）,-dp/dtmax和NO水平均明显高于氨氯地平组（P＜0.05）.结论 丹酚酸联合氨氯地平对高血压合并高脂血症大鼠模型的心血管具有协同保护效应,其可能通过保护血管内皮功能,抑制RAAS系统激活实现.     

Effects of Mechanical,Cold, Gustatory,and Combined Stimulation to the Human Anterior Faucial Pillars

Dysphagia - Abstract Tactile–Thermal Application (TTA) is a therapy technique designed to enhance the swallowing response in persons with dysphagia. In this study, TTA was broken down into...