Association Of IL-6in Serum With Expression Of Claudins Protein In Intestinal Epithelium From Rats With Severe Acute Pancreatitis

Objective To observe the changes of IL-6in Serum and the expressions of claudins protein in intestinal epithelium in severe acute pancreatitis rats, and investigate the relationship between the expression of claudins protein and the serum levels of IL-6in intestinal mucosa barrier damage.Methods58SD rats, weighting320-350g, were randomly divided into control group (n=10) and experimental group(n=48). The experimental group was divided four time points (3,12,24,48h). Before the experiment, all the rats were forbidden breeding for12h, drinking freely. The experimental group rats were intraperitoneal injected with L-arginine (2.5g/kg×2) in an interval of1hour, the control group were injected the same volume of0.9%sodium chloride in the same way and were killed at the end of last injection after drawing2ml blood from the internal jugular vein blood. The experimental group were randomly killed at last injection of3h,12h,24h,48h after drawing2ml blood from the internal jugular vein blood. Pancreatic tissue were stained by HE and observed under microscope. The ultrastructural of intestinal epithelial cells were observed under electron microscope and determined expression of intestinal epithelial cells tight junction protein claudins with immunohistochemical. The levels of serum IL-6were detected by ELSIA, and endotoxin levels were detected by LAL, PCR method was used to detecte bacteria DNA segments.Results The pancreatic tissue of control group had no hemorrhage and necrosis, the experimental group were no changes at3h, but the pancreatic tissue had hemorrhage and necrosis at12h,24h,48h. The ultrastructure of intestinal epithelium had no abnormal, the experimental group were no changes at3h, however, the intestinal epithelium were fractured and fall off, the intercellular were broadening at the other time points. The levels of IL-6in control group and experimental group were0.312±0.030、0.326±0.037、0.337±0.016、0.359±0.022、0.378±0.036, the experimental group had a significantly higher levels of IL-6than control group (P<0.05); the levels of endotoxin in control group and experimental group were0.028±0.004、0.155±0.014,0.274±0.020,0.352±0.017,0.490±0.0523, the experimental group had a significantly higher levels of endotoxin than control group (P<0.05); the bacterial translocation rate of3h experimental group had no significantly difference with control group(P=0.074, P>0.05), however、12h、24h、48h experimental groups had a significantly difference with control group(P<0.05); the claudins protein were uniformly distributed at the top of the intestinal epithelial cells by immunohistochemical in control group, but the experimental group were not evenly distributed in the intestinal epithelial cells. The average optical density value in control group and experimental group were0.3578±0.002、0.3531±0.0020、0.3513±0.0018、0.3492±0.0016.0.3185±0.0023, the3h experimental group had no statistical differences with control group (P>0.05), the other time points optical density were significantly lower than control group (P<0.05). The lower expression of claudins protein in intestinal epithelium had significantly (r=0.735, P<0.05) associated with the higher levels of IL-6in serum.Conclusions The serum levels of IL-6are rise in early stage for severe acute pancreatitis rats, and may cause the low expression of claudins protein in the intestinal epithelial cells.