NF-kappaB involvement in the induction of high affinity CAT-2 in lipopolysaccharide-stimulated rat lungs

BACKGROUND: Endotoxemia stimulates nitric oxide (NO) biosynthesis through induction of inducible NO synthase (iNOS). Cellular uptake of L-arginine, the sole substrate for iNOS, is an important mechanism regulating NO biosynthesis by iNOS. The isozymes of type-2 cationic amino acid transporters, including CAT-2, CAT-2A, and CAT-2B, constitute the most important pathways responsible for trans-membrane L-arginine transportation. Therefore, regulation of CAT-2 isozymes expression may constitute one of the downstream regulatory pathways that control iNOS activity. We investigated the time course of enzyme induction and the role of nuclear factor-kappaB (NF-kappaB) in CAT-2 isozymes expression in lipopolysaccharide-(LPS) treated rat lungs. METHODS: Adult male Sprague-Dawley rats were randomly given intravenous injections of normal saline (N/S), LPS, LPS plus NF-kappaB inhibitor pre-treatment (PDTC, dexamethasone, or salicylate), or an NF-kappaB inhibitor alone. The rats were sacrificed at different times after injection and enzyme expression and lung injury were examined. Pulmonary and systemic NO production were also measured. RESULTS: LPS co-induced iNOS, CAT-2, and CAT-2B but not CAT-2A expression in the lungs. Furthermore, NF-kappaB actively participated in LPS-induction of iNOS, CAT-2, and CAT-2B. LPS induced pulmonary and systemic NO overproduction and resulted in lung injuries. Attenuation of LPS-induced iNOS, CAT-2, and CAT-2B induction significantly inhibited NO biosynthesis and lessened lung injury. CONCLUSION: NF-kappaB actively participates in the induction of CAT-2 and CAT-2B in intact animals. Our data further support the idea that CAT-2 and CAT-2B are crucial in regulating iNOS activity.     

Microdialysis for measurement of hepatic and systemic nitric oxide biosynthesis in septic rats

BACKGROUND: We sought to compare two techniques, microdialysis and repeated blood withdrawal, for serial assessment of hepatic and systemic nitric oxide (NO) biosynthesis in septic rats. METHODS: Rats were randomly allocated to either microdialysis or blood withdrawal groups. Two microdialysis probes, one in liver and the other in right atrium, were placed in rats in the microdialysis group. Half of the rats from each group were then given lipopolysaccharide (LPS) to induce NO production. The other half of the rats from each group were injected with vehicle (normal saline) to serve as controls. In the microdialysis group, dialysate (30 microl) was collected every 30 min. In the blood withdrawal group, 0.3 ml of blood was drawn every 30 min. Sampling was performed up to 6 h after injection of LPS or vehicle. Hemodynamics, hepatic and systemic NO concentrations, and iNOS expression in harvested liver tissues were assayed. RESULTS: Repeated blood withdrawal by itself caused a significant decrease in blood pressure and induced hepatic iNOS expression. Microdialysis, on the contrary, reliably detected LPS-induced NO production without resulting either in hemodynamic changes or in iNOS induction in liver tissue. CONCLUSIONS: Microdialysis provides serial measure of hepatic and systemic NO concentrations in LPS-treated rats without the need for removal of tissue.     

Platonin attenuates LPS-induced CAT-2 and CAT-2B induction in stimulated murine macrophages

BACKGROUND: Platonin, a cyanine photosensitizing dye, is a potent immunomodulator that suppresses acute inflammation. Platonin not only inhibits interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha production but also improves circulatory failure in septic rats. In addition, platonin reduces plasma nitric oxide (NO) formation during sepsis. However, the effects of platonin on inducible NO synthase (iNOS) and cationic amino-acid transporter (including CAT-2, CAT-2 A, and CAT-2B) expressions during sepsis remain uninvestigated. METHODS: Five groups of confluent murine macrophages (RAW264.7 cells) were randomly allocated to receive a 1-h pretreatment of one of five doses of platonin (0.1 microM, 1 microM, 10 microM, 100 microM, or 1000 microM) followed by lipopolysaccharide (LPS; 100 ng ml(-1)). For negative, positive, and platonin control, three other groups of cell cultures were randomly allocated to receive phosphate-buffered saline, LPS, or platonin (1000 microM). The cultures were harvested after exposing them to LPS for 18 h or a comparable duration in those groups without LPS. NO production, L-arginine transport, and expression of the relevant enzymes were then evaluated. RESULTS: Platonin significantly attenuated LPS-induced up-regulation of iNOS expression and NO production in stimulated murine macrophages in a dose-dependent manner. Platonin also significantly inhibited up-regulation of CAT-2 and CAT-2B expression as well as L-arginine transport in LPS-stimulated murine macrophages in a dose-dependent manner. In contrast, CAT-2 A expression in murine macrophages was not affected by LPS and/or platonin. CONCLUSIONS: Platonin attenuates NO production and L-arginine transport in LPS-stimulated murine macrophages possibly through inhibiting iNOS, CAT-2, and CAT-2B expression.     

Differential regulation of L-arginine transporters (cationic amino acid transporter-1 and -2) by peroxynitrite in rat mesangial cells.

BACKGROUND: It has become evident that increased nitric oxide (NO) generation may be associated with production of reactive oxygen species, such as peroxynitrite (ONOO-). Peroxynitrite has been postulated to be responsible for several of the cytotoxic effects previously ascribed to NO. Since cellular arginine uptake has been shown to modulate nitric oxide synthase activity, we were intrigued to study the effect of ONOO- on arginine traffic in renal mesangial cells. METHODS: Arginine uptake, CAT-1 and CAT-2 mRNA expression by northern blotting analysis, and CAT-1 protein content using western blotting were determined in mesangial cells pre-treated with peroxynitrite (0.1 and 0.5 mM) for 2 h. RESULTS: Peroxynitrite induced a significant increase in arginine uptake and CAT-2 mRNA expression compared with untreated cells. In contrast, CAT-1 mRNA expression and protein abundance were diminished. CONCLUSIONS: In rat mesangial cells, peroxynitrite augments arginine uptake via augmentation of CAT-2 while decreasing CAT-1 expression.     

Predictive value of exhaled nitric oxide and aerobic capacity for sepsis complications after liver transplantation

Our objective was to investigate the predictive value of fractional nitric oxide (NO) concentration in exhaled breath (FeNO) and aerobic capacity (peak VO₂) for postoperative sepsis in liver transplantation candidates. Patients were identified and charts of all consecutive patients were prospectively reviewed. Bacterial sepsis represented the commonest postoperative complications (30%), which was attributed to peritonitis, pneumonia, and catheter‐related infections. Preoperative FeNO and peak VO₂ values were lower in patients with postoperative sepsis. Patients with sepsis required higher needs for mechanical ventilation and ICU length of stay. Inverse correlation was found between logarithmically FeNO‐transformed data and systolic pulmonary artery pressure (r = ?0.348; P = 0.018). Multivariate analyses using bootstrap sampling method indicated that odds of sepsis were associated with lower values of peak exercise VO₂ [OR = 0.790 (0.592; 0.925)] and reduced log(FeNo) [OR = 0.027 (0.001; 0.451)], but not with higher MELD scores [OR = 1.141 (0.970; 1.486)]. By evaluating the cutoff for the ROC curves in each bootstrap resampling, median and 95% confidence interval were calculated for peak VO₂: 17 [16.2; 22] ml/kg/min and FeNO: 17.2 [13.0; 33.9] ppb. We conclude that low peak exercise VO₂ and reduced FeNO may help identify patients who are at risk to develop perioperative sepsis.     

L-精氨酸预处理对肝硬化大鼠肝脏缺血再灌注损伤保护作用的实验研究

目的 探讨L-精氨酸(L-arginine,L-arg)预处理对硬化肝脏缺血再灌注(ischemia-reperfusion,I/R)损伤的保护作用及机制.方法 采用硫代乙酰胺(thioacetamide,TAA)复制大鼠肝硬化模型,然后阻断第5叶入肝血流30 min,再灌注60 min,建立部分肝缺血再灌注模型.24只肝硬化大鼠随机分成4组(n=6):①肝硬化大鼠对照组(对照组),仅分离肝周围韧带,不进行肝门阻断及再灌注;②肝硬化缺血再灌注组(缺血再灌注组);③L-精氨酸预处理组(精氨酸组);④L-硝基精氨酸甲酯(L-nitro-arginine-methy L-ester,L-NAME)预处理组(硝基精氨酸甲酯组).后三组分别于缺血前15 min经门静脉给予生理盐水、L-arg和L-NAME处理,测定再灌注后肝内门-体分流、血清门冬氨酸转氨酶(aspartate aminotransferase,AST)、丙氨酸转氨酶(alanine aminotransferase,ALT)、乳酸脱氢酶(lactate dehydrogenase,LDH)和肝组织超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(mal-ondialdehyde,MDA)、一氧化氮(nitric oxide,NO)、三磷酸腺苷酶(adenosine triphosphatase,ATPase)等的变化.采用门静脉连续输注山梨醇法.测定肝脏山梨醇摄取率,计算肝内门.体分流.结果 缺血再灌注组与对照组比较:功能性肝血流量(funotional hepatic blood flow,FHBF)、SOD显著降低(P<0.01),肝内分流率、肝内分流量(intrahepatic shunt flow,IHSF)、MDA、ALT、AST、LDH显著升高(P<0.01或P<0.05);精氨酸组与缺血再灌注组比较:NO、FHBF、SOD、Na+/K+-ATPase、Ca2+-ATPPase、Mg2+-ATPase显著升高(P<0.01或P<0.05),肝内分流率、lHSF、MDA、ALT、AST、LDH显著下降(P<0.01或P<0.05);硝基精氨酸甲酯组与缺血再灌注组比较:NO、FHBF显著下降(P<0.01),IHSF、MDA显著升高(P<0.01).结论 L-arg对硬化肝脏缺血再灌注损伤有保护作用,其保护机制是通过增加肝脏内源性NO,从而减少肝内门-体分流,增加功能性肝血流以及改善细胞能量代谢而实现的.     

Direct visualization of nitric oxide release by liver cells after the arrest of metastatic tumor cells in the hepatic microvasculature

BACKGROUND: Our previous studies have shown that the injection of B16F1 melanoma cells into the mesenteric vein can induce the rapid local release of nitric oxide (NO) in the liver, causing apoptosis of the melanoma cells in the liver sinusoids and inhibiting the subsequent formation of hepatic metastases. In this study, we have investigated the distribution and cellular source of NO in this model. MATERIALS AND METHODS: In situ liver perfusion was established in both wild-type (wt) and endothelial nitric oxide synthase knockout (eNOS KO) C57BL/6 mice. A specific fluorescent NO probe, 4,5-diaminofluorescein diacetate (DAF-2 DA) (5 micromol/L), was perfused into the portal venous system to label the liver tissue. Then, a MitoTracker Orange labeled B16F1 melanoma cell suspension (2 x 10(6) cells/ml) was injected through a portal vein catheter by a peristaltic pump. Images of the liver tissue were taken by confocal microscopy from a selected area to determine the cellular source of NO. For quantification, the fluorescence intensity of this area was measured over time by Fluoview software. RESULTS: Diaminotriazolofluorescein (DAF-2T) fluorescence (indicating NO generation) was detected in hepatic parenchymal cells located in the periportal region in both wt C57BL/6 and eNOS KO C57BL/6 mice and was intensified by increased flow rate in the portal venous system. The B16F1 cells arrested in the periportal sinusoids, corresponding to zone 1 of the hepatic acinus. DAF-2T fluorescence was expressed by both sinusoidal lining cells and hepatocytes at the site of tumor cell arrest. The fluorescence intensity of these cells increased approximately 2-fold over a time of 500 s. In contrast, there was no increase in the fluorescence intensity of the sinusoidal lining cells and hepatocytes in mice perfused with buffer or in eNOS KO mice perfused with B16F1 cells. CONCLUSION: This study demonstrates that NO is produced by hepatic parenchymal cells mainly located in the periportal zones and that the arrest of the B16F1 melanoma cells causes an eNOS-dependent local burst of NO by the sinusoidal lining cells and hepatocytes in the periportal areas.     

一氧化氮在大鼠异种肝移植急性排异中的作用及其黄递酶组化研究

目的：探讨一氧化氮（NO）在肝移植急性反应中的功能作用及NO合酶 （NOS）的细胞定位。方法：应用金黄地鼠至大鼠异种原位肝移植急性排斥及大鼠同基因原位肝移植动物模型,观察L－NMMA对受体存活期,ALT,TGF-α及移植肝的病理影响。应用NADPH－d组化染色观察NOS的活性及其细胞来源,结果：表明L－NMMA可明显降低异种肝移植受体存活期,加剧其肝功能恶化、上调TGF-α、加剧移植肝的病理损害、异种肝移植组NADPH－d组化染色呈强阳性,主要在肝实质细胞及浸润炎性细胞表达,结论：NO在大鼠肝移植急性排斥反应中可能具有重要的免疫保护作用。     

Protective effect of a prostaglandin oligomer on liver mitochondria in situ: time-shared measurements of fluorescence and reflectance in the cold-preserved rat liver

The protective effect of a new oligomeric derivative of prostaglandin B₂, known as OC-5186, was evaluated using time-sharing spectrofluorometry in the coldpreserved rat liver. Experiments were divided into three groups: in group A, a 5000 ng dose of OC-5186 was administered via the peripheral vein, 1000 ng via the portal vein, and 200 ng/ml in University of Wisconsin (UW) solution; in group B, the OC-5186 dosage was ten times greater than that in group A; in group C (control group), liver procurement and storage were performed without OC-5186. At 0, 12, and 24 h after cold preservation at 4°C, the liver was perfused for 30 min at 12°C with oxygenized Krebs-Henseleit solution, after which the perfusate was switched to deoxygenized Krebs-Henseleit solution. Time sharing spectrofluorometry was used to follow NADH fluorescence at 450 nm with a 360-nm excitation wavelength, as well as the reflectance of cytochrome aa ₃ with 605 minus 620 nm from oxidation to reduction. Rate constants of NADH fluorescence and cytochrome aa ₃ reflectance were used as indices of integrity of the mitochondrial respiratory chain. In group C, the rate constant of NADH fluorescence decreased significantly (P<0.05) from the control value of 8.31±0.21×10^-3 (sec^-1) to 4.97±0.15×10^-3 and 5.58±0.16×10^-3 (mean±SEM) at 12 and 24 h after cold preservation, respectively. By contrast, in groups A and B, the rate constant of NADH fluorescence was maintained at significantly (P<0.05) higher levels of 6.57±0.54×10^-3 and 7.29±0.48×10^-3, and 6.94±0.44×10^-3 and 6.86±0.44×10^-3 at 12 and 24 h, respectively. The rate constant of cytochrome aa ₃ reflectance between the OC-5186 groups and the control group was not significant. It is concluded that OC-5186 has a protective effect on the mitochondrial respiratory chain against cold-preservation and/or reperfusion injury.     

Direct evidence that induced nitric oxide production in hepatocytes prevents liver damage during lipopolysaccharide tolerance in rats

BACKGROUND: The role of nitric oxide (NO) in lipopolysaccharide (LPS) tolerance in the liver has been investigated in a number of previous studies, but it is still not clear whether NO is cytotoxic or cytoprotective. The aims of this study were to investigate whether low-dose LPS (LLPS)-induced hepatic production of NO is beneficial and to clarify the origins of cytoprotective NO-producing cells in the liver during LPS tolerance. MATERIALS AND METHODS: Male Wistar rats received saline or LLPS intraperitoneally (i.p.; 0.01-1000 microg/kg) followed by a high dose of LPS (HLPS, 5 mg/kg) at various time intervals (4-16 h). NG-nitro-L-arginine methyl ester (L-NAME) was used to investigate the effects of inhibition of NOS. 4,5-Diaminofluorescein (DAF-2) was used to identify NO-producing cells in isolated liver cells in vitro. At various time points (4-16 h) after saline or LLPS (1 microg/kg, i.p.) injection, hepatocytes and Kupffer cells were isolated, incubated in 7 microm DAF-2 diacetate, and perfused with Krebs solution. Illumination at 495 nm revealed DAF-fluorescence (515 nm) in isolated cells under confocal laser fluorescence microscopy. The NO production in hepatocytes and Kupffer cells was assessed by the number of labeled cells per 1000 cells or per 100 cells, respectively. RESULTS: Pretreatment with LLPS (0.1-100 microg/kg) resulted in a significant reduction (maximal at 8 h) of the HLPS-induced liver damage. L-NAME abolished the LLPS-induced protection. The NO production in hepatocytes was significantly increased and reached a maximum of 84% of all cells 8 h after LLPS administration. By contrast, the NO production in Kupffer cells remained constant at 95%, even following preinjection of LLPS. CONCLUSION: LLPS-induced NO in hepatocytes, but not in Kupffer cells, exhibits cytoprotective effects on HLPS-induced liver damage, suggesting that NO has a beneficial role in the induction of the early phase of LPS tolerance.     

不同预处理对大鼠肝移植供肝保护作用的探讨

目的 通过应用缺血、加热等多种手段对大鼠供肝进行移植术前的预处理,比较各种预处理方法对大鼠肝移植供肝缺血再灌注损伤的保护作用. 方法 将SD大鼠50只,随机分为5组:半肝缺血预处理组、脾脏缺血预处理组、热休克预处理组、热休克+缺血预处理组及手术对照组,分别进行肝脏预处理后行模拟原位肝移植术,术后检测胆汁流量,术后24 h检测血清ALT,AST,ALP水平并观察肝脏形态学变化. 结果 半肝缺血预处理组、热休克预处理组移植后胆汁分泌量多于对照组,血清ALT,AST水平明显低于对照组(P<0.05);热休克+缺血预处理组的血清ALT水平低于对照组(P<0.05),胆汁分泌量及血清AST与对照组没有显著差异;脾脏缺血预处理组的胆汁分泌量多于对照组,血清ALT水平低于对照组(P<0.05). 结论 肝脏缺血预处理初始阶段保护作用最明显,将缺血及热休克预处理两种方法联合处理大鼠时,其保护作用弱于单独缺血或单独热休克的预处理方法;脾脏缺血预处理也具有保护肝脏的作用.     

Effects of taurine on liver preservation in UW solution with consecutive ischemic rewarming in the isolated perfused rat liver

Taurine (2-aminoethane sulfonic acid) is a physiologic amino acid involved in cellular osmoregulation in various species including man. This study was intended to compare the respective effects of cold storage and consecutive ischemic rewarming of the liver on postischemic hepatic flow and hepatocellular outcome upon reperfusion with or without the addition of taurine to the preservation medium. Livers from male Wistar rats were rinsed free of blood via the portal vein and stored ischemically at 4 °C in UW solution. Livers from group 1 were then rinsed again with 10 ml Ringer's solution and reperfused with Krebs-Henseleit buffer at a constant pressure of 10 mmHg for 45 min at 37 °C in a nonrecirculating manner. Livers from groups 2 and 3 were subjected to 30 min of warm ischemia subsequent to cold storage and prior to reperfusion with 10 mM taurine added to the UW solution in group 3. While there were only very few signs of hepatic injury in group 1, the additional period of warm ischemia (group 2) led to a significant reduction in early perfusate flow and enhanced enzyme leakage from the livers during postischemic rinse and reperfusion. Livers in group 3 exhibited an amelioration in hepatic circulation and significantly reduced enzyme release as compared to group 2. The results clearly demonstrate a remarkable impact of postischemic rewarming on graft viability. Furthermore, the addition of taurine to the preservation medium was shown to improve hepatic circulation and enhance viability of the liver upon reperfusion.     

The characterization of reconstituted passenger leukocytes on the induction of tolerance in rat liver transplantation

The tolerance induced by orthotopic liver transplantation [DA (RT1^a) rats to PVG (RT1^c) rats] can be prevented by total body irradiation of the donor rat. Reconstitution of the irradiated donor with DA splenic leukocytes reintroduces this tolerance. To investigate the major histocompatibility complex (MHC) specificity of passenger leukocytes, irradiated DA donors were reconstituted by third-party BN (RT1ⁿ) splenic leukocytes. The reconstitution with BN splenocytes re-established DA-specific tolerance in PVG recipients, as confirmed by subsequent DA cardiac allografting, while BN hearts were rejected with second-set tempo. To determine which cell components play an important role in re-establishing liver graft tolerance, DA splenic leukocytes were further purified into three types: T, B, and adherent cells. Only “T-cell-enriched” preparations restored liver graft tolerance in three out of five PVG recipients. These results suggest that passenger leukocytes of differing MHC types can help to induce liver-specific tolerance and that T cells in the liver graft may be essential to regulate tolerance induction. Received: 31 December 1996 Received after revision: 14 April 1997 Accepted: 15 April 1997     

Detrimental effect of a non-selective nitric oxide synthase inhibitor on the energy state of the liver following acute endotoxemia in rabbits

Background : The effect of nitric oxide synthase (NOS) inhibitors in septic shock is very controversial. It is known that the administration of NOS inhibitors to normal subjects itself increases pulmonary vascular resistance with a concomitant decrease of cardiac output. Therefore, the hypothesis was tested that the detrimental effects of a non-selective NOS inhibitor on liver energetics in a rodent model of endotoxemia are mediated by the adverse pulmonary circulatory effect of the drug itself.
Methods : Twenty anesthetized rabbits were instrumented and two separate experiments (a magnetic resonance spectroscopic study and a hemodynamic study) were performed under similar conditions. Animals were assigned randomly to either a control group (group 1; animals received lipopolysaccharide (LPS) at a dose of 400 μg/kg alone) or a treatment group (group 2; animals received N^G-nitro-L-arginine methyl ester (L-NAME) at a dose of 7.5 mg/kg, 75 min after administration of LPS).
Results : In group 1, slight decreases in hepatic adenosine triphosphate (ATP) value were observed. In group 2, the decreases in ATP values were more prominent than those observed in group 1. LPS produced an acute drop in mean arterial pressure (MAP) with a concomitant increase in pulmonary vascular resistance (PVR) and a reduction in the cardiac output (CO) at 30 min after LPS. The administration of L-NAME caused a transient increase in MAP with a concomitant increase in systemic vascular resistance at 2 h after LPS. However, these changes in PVR and CO were more prominent than in group 1.
Conclusion : These results suggest that alterations within the pulmonary circulation may be a contributing factor which was responsible for the non-selective NOS inhibitor-induced acute hepatic energy derangement after LPS.     

Experimental varicocele in the rat: early evaluation of the nitric oxide levels and histological alterations in the testicular tissue

The relationship between varicocele and male infertility remains to be explained. Oxidative damage because of the testicular venous backflow may represent one of the causes of gonad injury and seems to precede the histological alteration. Therefore measuring the values of spermatic or intratesticular nitric oxide (NO) could be useful in evaluating this oxidative distress. The aim of this study is to assess the role of testicular NO in early detection of the damages induced by an experimental varicocele in the Wistar rat. A left varicocele was induced in 10 animals (group A). A control group of 10 rats was performed (group B). Animals were killed 3 months after the operation. Both testicles were harvested, weighed and sectioned in two equal parts: one for the evaluation of the NO level and the other one for histological examination. All the rats in group A showed a conspicuous dilatation of the left spermatic vein. The histopathological analysis was normal in both the groups. Biochemistry showed a meaningful statistical difference (P < 0.001) in the concentrations of NO among the specimens of the left and right gonads in group A but no difference was found in group B. The increase in NO values and the presence of other oxidant agents represent the first sign of testicular distress and it seems to anticipate histopathological changes. As it is well known that a great difference exist between human and animal sperm, NO could therefore in the future be taken into consideration together with others parameters for the evaluation of patient who is affected by varicocele.     

Quantitative studies of liver atrophy after portacaval shunt in the rat

BACKGROUND: It is well known that portacaval shunting ultimately leads to a decrease in liver volume and hepatic function, but the mechanism is uncertain. The aim of the present study was to evaluate the effect of portacaval shunting (PCS) upon the morphological changes that occur in the liver in rats after port caval anastomosis. MATERIALS AND METHODS: Sixty-six male rats underwent either PCS (n = 35) or sham operations (n = 31). Hormone levels were determined in blood samples taken just before removal and weighing of the livers. Hematoxylin and eosin-stained sections were used for quantitative morphometric analysis. Apoptosis, mitosis, and cellular organelles also were assessed quantitatively. RESULTS: There was a significant reduction in the liver mass together with testosterone levels in PCS rats in comparison with sham rats. The distance between presinusoidal and postsinusoidal vessels was reduced from 500 mum in the sham rats to 299 mum in the PCS rats (P = 0.000001). Within the same group, there was a significant reduction in the area of hepatocyte nuclei in zone 3 in comparison with zone 1. Electron microscopy revealed a highly significant (P = 0.0007) reduction in the membrane-bound cytoplasmic organelles of zone 3 hepatocytes in PCS rats in comparison with the sham rats. Apoptosis was increased in zone 3 in PCS rats (P = 0.00001), whereas in zone 1 of the same group, there was an associated increased in mitosis (P = 0.000001). Overall, the degree of apoptosis was in excess of mitosis, resulting in a general loss of liver mass. CONCLUSION: Morphometric analysis at cellular and subcellular levels confirms the morphological findings of liver atrophy in PCS rats. The mechanism of atrophy is a complex one. Portacaval shunting leads to hepatic atrophy that, in turn, results in microcirculatory and hormonal changes that further contribute to liver cell loss in this animal model.     

饮酒对大鼠生精细胞iNOS,Bcl-2基因表达的影响

目的 探讨酒精对大鼠睾丸诱导型一氧化氮合酶（iNOS）、Bcl-2基因表达和生精细胞凋亡的影响。方法30只成年健康SD雄性大鼠随机均分为对照组、低剂量组和高剂量组，用不同剂量的酒精灌胃成年大鼠26d（两个生精周期）后，免疫组织化学法（SP法）检测睾丸iNOS、BCl-2基因表达的变化；原位缺口末端标记法（TUNEL法）检测细胞凋亡指数（A1）的变化。结果 与对照组相比，低剂量组大鼠睾丸iNOS、Bcl-2基闪表达强度和细胞凋亡指数（A1）无明显变化（P〉0．05）：而高剂量组与对照组和低剂量组相比，iNOS表达显著增强（P〈0．01），Bcl-2基因表达明显减弱（P〈0．01，P〈0．05），细胞凋亡指数则增加（P〈0.01）。结论 长期大量饮酒可以诱导睾丸生精细胞凋亡增加，iNOS与Bcl-2基因表达的改变是重要原因之一。