N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸对Smad7／转化生长因子β1／整合素连接激酶信号通路的影响

Effect of AcSDKP against renal interstitial fibrosis and Smad7/TGF-βl/ILK signal pathway

目的探讨N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸（AcSDKP）对大鼠单侧输尿管结扎梗阻致肾间质纤维化的作用及其可能机制。方法54只SD大鼠随机分为假手术对照组（C组）、模型组（M组）和AcSDKP治疗组（T组），其中M组建立单侧输尿管结扎梗阻致。肾间质纤维化模型，T组并给予AcSDKP治疗。术后第3、7和14天处死各组大鼠，并将肾的1／2制作切片行HE和Masson染色观察肾脏病理学动态改变，免疫组化法检测。肾间质组织内转化生长因子81和Smad7、α-平滑肌肌动蛋白的表达。RTPCR测肾小管上皮细胞整合素连接激酶mRNA。结果HE染色及Masson染色显示，M组术后随时间延长肾小管间质病变加重，程度同期最重，T组病变程度介于同期M组及C组之间。C组基本正常，结果有统计学差异（P〈0．05）。免疫组化及RT-PCR结果：M组转化生长因子β1、α-平滑肌肌动蛋白和整合素连接激酶mRNA表达随时间延长逐渐上调，程度同期最高。T组蛋白表达程度介于M组及C组之间。C组表达最低，结果有统计学差异（P〈0．05）；同期T组肾间质Smad7表达明显上调，低于同期C组，但高于M组，结果有统计学差异（P〈0．05）。结论AcSDKP对大鼠肾间质纤维化有抑制作用，其机制可能通过增加大鼠UUO模型中Smad7蛋白的表达抑制转化生长因子β1／整合素连接激酶信号转导。

Objective To observe the effect of N-acetyl-seryl-aspartic acid-lysyl-proli-ne（AcSD- KP） on renal interstitial fibrosis made by unilateral ureteral obstruction （UUO） in rats and explore the possible mechanism. Methods Fifty-four adult SD rats were randomly divided into three groups., sham operation group （C group）, UUO model group （M） and AcSDKP treatment group （T）. In UUO model group, renal interstitial fibrosis model was established by UUO, and in T group AeSDKP was given. The animals were sacrificed at 3rd ,7th,and 14th day after operation, and the 1/2 left kidney was taken and cut into 2-μm thick sections for HE and Masson staining. The expression of TGF-β1 ,Smad7 and α- SMA was detected by using immunohistochemistry in renal interstitial tissues. ILK mRNA was meas- ured by using RT-PCR. Results With the time,the tubulointerstitial lesions in M group were aggra- vated most significantly, followed by T group and C group （P〈0. 05）. Immunohistochemistry and RT-PCR results revealed that the expression of TGF-β1, α-SMA and ILK mRNA in M group was gradually increased with time, the highest level at the same period, and higher than T group and C group, followed by T group and C group （P〈0. 05）. The expression of smad7 in M group was gradu- ally reduced with time, followed by T group and C group（P〈0. 05）. Conclusions AeSDKP can allevi- ate the interstitial fibrosis of the kidney possibly by inhibiting the signal pathway of TGF-β1/ILK through increasing the expression of Smad7 protein in renal interstitial tissues.