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Alterations of tumor necrosis factor-alpha and interleukin 6 production and activity of the reticuloendothelial system in experimental obstructive jaundice in rats.

ABSTRACT: Immunological changes are well recognised in obstructive jaundice. The aim of this study was to monitor plasma tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) levels in rats with obstructive jaundice.The ability of splenocytes and peritoneal exudate cells (PEC) to produce these cytokines both spontaneously and on induction with lipopolysaccharide (LPS), was compared in rats with and without obstructive jaundice (OJ). The activity of the reticuloendothelial system (RES) was also measured.Serum cytokine levels in OJ rats were higher than in control rats. PEC cultures produced significantly more IL-6, compared with control rats, declining thereafter. TNF-alpha activity in the splenocyte cultures of OJ rats was also higher than in the control group. Pronounced differences were found in the ability to produce TNF-alpha by PEC, i.e., TNF-alpha production was much stronger on day 7 in OJ rats than in controls. On day 14 TNF-alpha production was much lower and the spontaneous response was equal to the LPS-induced one. On day 21 the cells of OJ rats partially regained the ability to produce TNF-alpha RES activity of OJ rats was significantly suppressed in the liver and spleen, whereas the phagocytic activity in the lungs was elevated.We have demonstrated that the immune reactivity of OJ rats, initially elevated, underwent subsequent depression. The study also revealed a major effect of the operation alone on the studied parameters.

SUBMITTER: Dawiskiba J

PROVIDER: S-EPMC2023907 | biostudies-other | 2002

REPOSITORIES: biostudies-other

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Project description:Obesity is often associated with insulin resistance, low-grade systemic inflammation, and reduced plasma adiponectin. Inflammation is also increased in adipose tissue, but it is not clear whether the reductions of adiponectin levels are related to dysregulation of insulin activity and/or increased proinflammatory mediators. In this study, we investigated the interactions of insulin, tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) in the regulation of adiponectin production using in vivo and in vitro approaches. Plasma adiponectin and parameters of insulin resistance and inflammation were assessed in a cohort of lean and obese insulin-resistant subjects. In addition, the effect of insulin was examined in vivo using the hyperinsulinemic-euglycemic clamp, and in adipose tissue (AT) cultures. Compared with lean subjects, the levels of total adiponectin, and especially the high-molecular-weight (HMW) isomer, were abnormally low in obese insulin-resistant subjects. The hyperinsulinemic clamp data confirmed the insulin-resistant state in the obese patients and showed that insulin infusion significantly increased the plasma adiponectin in lean but not obese subjects (P < 0.01). Similarly, insulin increased total adiponectin release from AT explants of lean and not obese subjects. Moreover, expression and secretion of TNF-α and IL-6 increased significantly in AT of obese subjects and were negatively associated with expression and secretion of adiponectin. In 3T3-L1 and human adipocyte cultures, insulin strongly enhanced adiponectin expression (2-fold) and secretion (3-fold). TNF-α, and not IL-6, strongly opposed the stimulatory effects of insulin. Intriguingly, the inhibitory effect of TNF-α was especially directed toward the HMW isomer of adiponectin. In conclusion, these studies show that insulin upregulates adiponectin expression and release, and that TNF-α opposes the stimulatory effects of insulin. A combination of insulin resistance and increased TNF-α production could explain the decline of adiponectin levels and alterations of isomer composition in plasma of obese insulin-resistant subjects.

Project description:Postoperative acute renal failure in patients with obstructive jaundice is still a serious clinically complication, yet the mechanisms remain unclear. Renin-angiotensin-aldosterone system (RAAS) plays a central role in renal disease progression. Several lines of evidence shows that angiotensin-converting-enzyme-2 (ACE2), a main effector of RAAS acts as a local regulator for renal protection. This study aims to investigate the role of ACE2 and the effect of spironolactone treatment in obstructive jaundice(OJ) rats with renal injury. The rats with obstructive jaundice were established by bile duct ligation. Total bilirubin (TBil), serum creatinine (Scr) and the expression of ACE2 in kidney tissue of obstructive jaundice rats were detected. Comparatively, the expression of ACE2, renin, angiotensin II (AngII), angiotensin-(1-7)[Ang-(1-7)], aldosterone and intercellular adhesion molecule 1 (ICAM-1) in kidney tissues after spironolactone administration were measured by ELISA. Renal necrosis, inflammation and fibrosis induced by OJ were also measured by HE staining and Masson staining. The correlation between the expression of ACE2 and TBil, also the Scr level were investigated. With the time of common bile duct ligation prolonged, the TBil and Scr concentration increased while the expression of ACE2 in OJ rats' kidney tissues decreased. However, after spironolactone intervention, the expressions of ACE2, renin, AngII, Ang-(1-7), aldosterone and ICAM-1 in kidney tissue were changed, moreover, necrotic, inflammatory and fibrotic condition was also decreased. The relationship between the mRNA expression of ACE2 and TBil/Scr was observed to be moderately negatively correlated (r = -0.516, R2 = 0.292, P < 0.01), (r = -0.576, R2 = 0.332, P < 0.01), respectively. RAAS exerted an important effect in the renal damage caused by OJ. Spironolactone intervention not only improved the degree of renal fibrosis induced by OJ, but also upregulated the ACE2 expression in the kidney of OJ rats and rescued the renal function.

Project description:BACKGROUND: Although clinical and experimental studies have demonstrated a correlation between obstructive jaundice and the development of sepsis, the mechanism has not been fully elucidated. PURPOSE: The aim of this study was to investigate the influence of biliary obstruction on bacterial translocation as a possible source of infection in cases of obstructive jaundice. MATERIAL AND METHODS: Two groups of 12 Wistar rats were examined: rats subjected to common bile duct (CBD) ligation (group A) and rats subjected to a sham operation (group B). After 7 days, blood samples were taken and liver, spleen, and mesenteric lymph nodes (MLNs) from the ileocecal area were removed, divided into small pieces, and cultured. Quantitative culture results were determined by the number of colony-forming units (CFU) per milliliter of homogenate. Bacterial translocation was defined as the presence of a positive culture of MLNs, blood, liver, and/or spleen. Samples for histopathological examination were taken from the mucosa of the ileum and the colon and evaluated for inflammatory and destructive changes. RESULTS: There was no evidence of bacterial translocation to MLNs, blood, spleen, or liver detected in any of the 12 sham-operated control rats. In contrast, bacterial translocation was demonstrated in 8 of the 12 CBD-ligated rats (P < 0.01). In all eight cases in which translocation occurred, Escherichia coli were cultured from the MLNs. There were no histological changes in the mucosal samples of the control animals. In the CBD-ligated rats, hyperemia, vacuolization, reduction of goblet cells, decreased mitotic activity, and infiltration by lymphocytes and polymorphonuclear leukocytes (PMNLs) were detected. Cases in which translocation occurred were significantly associated with decreased mitotic activity in the colon (r = -0.5, P < 0.01) and higher infiltration by PMNLs in the ileum (r = -0.62, P < 0.05). CONCLUSION: Obstructive jaundice in a rat model predisposes to bacterial translocation. This suggests a mechanism whereby jaundiced patients are susceptible to septic complication.

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Alterations of tumor necrosis factor-alpha and interleukin 6 production and activity of the reticuloendothelial system in experimental obstructive jaundice in rats.

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