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目的:观察腹腔注射脂多糖(LPS)对小鼠肾脏单核细胞趋化蛋白1(MCP-1)、诱导型一氧化氮合酶(iNOS)、过氧化物酶体增殖物活化受体γ(PPAR-γ)及其辅调节因子表达的影响。方法:雄性云南昆明小白鼠[(20±2)g]随机分成两组:LPS组,腹腔注射LPS(5mg/kg);对照组,腹腔注射等体积磷酸盐缓冲液。分别于0～72h后处死小鼠,检测血清尿素氮和肌酐变化;留取肾脏,EMSA法检测NF-κB及PPAR-γ的DNA结合活性;Real-time PCR法检测肾组织MCP-1、iNOS、PPAR-γ及其辅激活因子1(PGC-1)、类固醇受体辅激活因子1(SRC-1)、SRC-2、SRC-3及核辅抑制因子(NCoR)mRNA的表达;ELISA检测肾组织MCP-1蛋白表达,Western Blot检测肾组织核蛋白PPAR-γ表达;HE染色观察病理改变,免疫组织化学法观察肾组织巨噬细胞的浸润情况。结果:小鼠腹腔注射LPS后血清尿素氮升高明显(P<0.05),但血肌酐无明显变化。肾组织NF-κB的DNA结合活性在0.5h后即明显增高,而PPAR-γ的DNA结合活性早期增强,8h后开始减弱。与同时间点对照组及基础值相比,小鼠腹腔注射LPS后6h,12h及24h,肾组织MCP-1 mRNA及蛋白表达均显著增加(P<0.01);而iNOS mRNA表达在6h及12h后显著增加(P<0.01)。PPAR-γ及PGC-1 mRNA表达则显著下调(P<0.01),核内PPAR-γ蛋白含量早期升高,24h时显著下降(P<0.01)。SRC-1、SRC-2、SRC-3及NCoR mRNA的表达与对照组相比无显著差异。LPS作用后肾组织HE染色未见显著改变,免疫组化可见肾组织巨噬细胞浸润,最初主要分布在髓质肾小管周围,在48h及72h浸润更为明显,皮质肾小球周围也可见巨噬细胞浸润。结论:小鼠腹腔注射LPS后肾组织中NF-κB活性及相关炎症因子MCP-1和iNOS表达上调,肾组织内有明显的巨噬细胞浸润,表明处于炎症状态,而PPAR-γ及其辅激活因子PGC-1的表达下调可能与炎症发展相关。
Objective: To observe the effects of lipopolysaccharide (LPS) on the expression of MCP-1, iNOS, PPAR-γ) and its co-regulatory factor expression. METHODS: Male Kunming mice in Yunnan [(20 ± 2) g] were randomly divided into two groups: LPS group, intraperitoneal injection of LPS (5mg / kg), control group, intraperitoneal injection of an equal volume of phosphate buffer solution. The mice were killed after 0 ~ 72h, the changes of serum urea nitrogen and creatinine were detected. The kidneys were collected and the DNA binding activities of NF-κB and PPAR-γ were detected by EMSA. The expressions of MCP-1, iNOS , PPAR-γ and its coactivator 1 (PGC-1), and the expression of SRC-1, SRC-2, SRC-3 and NCoR. The expression of MCP-1 protein in renal tissue and the expression of nuclear protein PPAR-γ in renal tissue were detected by Western Blot. The pathological changes were observed by HE staining and the infiltration of macrophages in renal tissue was observed by immunohistochemical method. Results: After intraperitoneal injection of LPS, serum urea nitrogen increased significantly (P <0.05), but serum creatinine did not change significantly. The DNA binding activity of NF-κB in renal tissue was significantly increased after 0.5 h, while the DNA binding activity of PPAR-γ increased early and began to decrease after 8 h. The mRNA and protein expressions of MCP-1 in kidney were significantly increased at 6h, 12h and 24h after LPS injection in mice (P <0.01), while the expression of iNOS mRNA at 6h and 12h After a significant increase (P <0.01). The mRNA expression of PPAR-γ and PGC-1 was significantly down-regulated (P <0.01). The content of PPAR-γ in nucleus increased at early stage and decreased significantly at 24h (P <0.01). SRC-1, SRC-2, SRC-3 and NCoR mRNA expression compared with the control group no significant difference. There was no significant change in HE staining of renal tissue after LPS treatment. Immunohistochemistry showed infiltration of macrophages in renal tissue, initially mainly around the medullary tubules. The infiltration was more obvious at 48h and 72h, Macrophage infiltration. CONCLUSION: The expression of NF-κB and related inflammatory factors MCP-1 and iNOS in renal tissue of mice after intraperitoneal injection of LPS are up-regulated. There is obvious infiltration of macrophages in the kidney tissue, indicating that they are in an inflammatory state. However, PPAR-γ and its supplement Down-regulation of PGC-1 activation may be related to the development of inflammation.