Change of the Lymphocyte Stimulation Index and the Serum Immunoglobulin in Experimental Obstructive Jaundiced Rats

ABSTRACT

BACKGROUND: The high incidence of operative complications in patients with jaundice is associated with an impaired immune system, an increased systemic and portal endotoxemia due to the decreased hepatic reticuloendothelial function, and increased immune inhibitory factors such as bilirubin and bile acids. This study was designed to evaluate the immune response and the histological changes in rats with obstructive jaundice induced by common bile-duct (CBD) ligation. METHODS: Thirty-two male Wister rats weighing 250-320 gm were enrolled in this study and divided into 2 groups a control group and a CBD ligation group. Under general anesthesia, the CBD was ligated with silk and resected for the CBD ligation group, but it was only isolated for the control group. The rats were sacrificed at the lst, the 2nd, and the 3rd weeks after ligation, and we evaluated the chemistries of the liver function, the lymphocytes stimulation index, the serum immunoglobulin levels, and the histological changes in the bile-duct-ligated livers. RESULTS: 1. There was no statistical difference in the serum creatinine levels between the control and the CBD ligation groups. At the lst week in the CBD ligation group, the serum AST, ALT, and bilirubin levels were statistically higher than those of the control group (p<0.05), which were slightly increased thereafter. 2. The lymphocyte stimulation index (LSI) of peripheral lymphocytes in the CBD ligation group was significantly decreased with the passing of time, but that of the control group was not. The LSI of splenocytes was statistically higher than that of peripheral lymphocytes in the control group, and the LSI of splenocytes was significantly decreased at the lst and the 2nd weeks, but was only slightly decreased, without statistical significance, at the 3rd week, in the CBD ligation group. 3. The serum immunoglobulin G (Ig G) level was significantly decreased at the lst week in the CBD ligation group compared with that of the control group and was slightly decreased, without statistical significance, at the 2nd and the 3rd weeks in the CBD ligation group. The serum immunoglobulin A (Ig A) level was extremely low in all groups, but this result had no statistical significance. 4. After CBD ligation, livertissues showed progressive bile ductular proliferation in the portal tract and an infarct with inflammatory infiltration into the central vein area and cholestatic change. CONCLUSION: These results suggest that derangement of the liver functions, suppresed lymphocytes function, and decreased immunoglobulin production might be associated with impairment of the immune response in bile-duct-ligated rats.