ABSTRACT
BACKGROUND: Nowadays, angiotensin Ⅱ plays an important role in onset of diabetic nephropathy. Therefore, the nuclear factor-κB may have adjustive effects on angiotonin system of kidney tissue of diabetic rats. OBJECTIVE: To observe the relationship of activity of inhibitive nuclear factor-κB with angiotensin Ⅱ and its type 1 receptor mRNA expression of renal tissue of diabetic rats. DESIGN: Completely randomized group design, control experiment. MATERIALS: The experiment was conducted at the Experimental Animal Center, Sun Yat-sen University of Medical Sciences between March and April 2000. Fifty-one pure breed clean grade male Wistar rats were select ed. METHODS: ①Models were established in 39 rats. Streptozotocin dissolv ing in citric acid buffer (0.1 mmol/L,pH=4.5) were given to establish dia betic models with 60 mg/kg intraperitoneal injection. If the fasting blood glucose maintained above 13.9 mmol/L, the establishment of models was successful. The thirty-nine rats were randomly assigned into 3 groups: model group (n=17, without other interventional measure, feeding normally) and pyrrolidine dithiocar2. Bamate (PDTC) (active inhibitor of nuclear fac tor-κB) interventional group [n=22, PDTC at the dose of 20 mg/kg were given with intraperitoneal injection, twice a day]. Other 12 rats were as normal control group, did not make into diabetic models with normal breeding. ②After feeding for 18 weeks kidneys were got in every group. The activity of nuclear factor-κB was detected with electrophoretic mobility shift assay. The expression of type 1 receptor mRNA of angiotensin Ⅱ was measured with reverse transcription polymerase chain reaction (RT-PCR). Contents of angiotonin Ⅰ and angiotensin Ⅱ were tested with Radio Im munoassay (RIA). Activity of rennin was referred to that the result of the level of angiotonin Ⅰ at 37 ℃ water bath subduced to that at 4 ℃. ③Dif ference of measurement data was compared with single factor analysis of variance. After normal transformation, the non-normal distribution data were conducted with statistical disposal. MAIN OUTCOME MEASURES: Comparison of contents of angiotensin Ⅰ and Ⅱ, activities of rennin and nuclear factor-κB and expression of type 1 receptor mRNA of angiotensin Ⅱ in renal tissues of rats of each group. RESULTS: In the normal control group, model group and PDTC interven tional group 1, 6 and 13 rats were dropped out, respectively, so 11, 11 and 9 rats in each group were involved in the result analysis. ①Activity of nu clear factor-κB: It was higher significantly in the model group than that in the normal control group and PDTC interventional group (P ＜ 0.01 ). It was similar between the normal control group and the PDTC interventional group. ②Activity of rennin of renal tissue: It was similar among the 3 groups. ③Content of angiotonin Ⅰ of renal tissue: It was higher obviously in the model group that that in the normal control group and the PDTC interventional group (P ＜ 0.01 ). ④Content of angiotensin Ⅱ in renal tissue: It was similar between the model group and the normal control group. It was lower markedly in the PDTC interventional group than that in the model group and the normal control group (P ＜ 0.01 ). Expression of type 1 receptor mRNA of angiotensin Ⅱ: It was lower remarkably in the model group than that in the normal control group (P ＜ 0.01 ). It was lower dis tinctly in the PDTC interventional group than that in the model group and the normal control group (P ＜ 0.01 ). CONCLUSION: The increase of activity of nuclear factor-κB in renal tissue of diabetic rats can inhibit the activity of nuclear factor-κB, which will induce the reduction of the level of angiotensin Ⅱ and expression of type 1 receptor mRNA of angiotensin Ⅱ in renal tissue of diabetic rats.