Abstract: Objective: To establish the sepsis rat model and explore the structure and function change of kidney and the expression of nuclear factor B(NF-B) in kidney.Methods: Thirty-six male Sprague-Dawley rats were randomly divided into sham operation group(Sham group) and cecal ligation and puncture group(CLP group)(18 rats each group).The sepsis rat model were established by cecal ligation and puncture in CLP group,and the Sham group didn't do cecal ligation and puncture processing.The heart rate(HR),mean arterial perssure(MAP),the levels of creatine(Cr) and blood urea nitrogen(BUN) and kidney structure change of two groups were observed at 6,12 and 24 hours after operation.The expression of NF-B in kidney was observed by immunohistochemical staining.Results: Compared with time-matched Sham group,the HR and MAP of CLP group increased at 6 to 12 hours after operation(P 0.01 and P 0.05),MAP of CLP group decreased at 24 hours(P 0.01).Compared with time-matched Sham group,the level of BUN of CLP group increased at 6 to 24 hours(P 0.05 to P 0.01),the level of Cr significantly increased at 24 hours(P 0.01) in CLP group.Histology showed the glomus gore and shrinkage of renal corpuscle and renal capsule cavity expanding.The number of glomus with gore and shrinkage together with renal tubule epithelial cell swelling and necrosis increased with the disease duration in CLP group.Immunohistochemistry revealed that NF-B located mainly in cytoplasm and its staining was light in Sham group,and NF-B located mainly in cell nucleus and its staining was deep in CLP group.Conclusions: With the course extension of sepsis,the injury of rat kidney structure and function aggravates.The high expressions of NF-B in cell nucleus suggest that the activation of NF-B may be an important factor to promote renal structure and functional damage.