胆酸对代谢性炎症模型大鼠炎性因子及PPARα和LXRα表达与分布的影响

Effects of cholic acid on inflammatory factors,expression and distribution of PPARα and LXRα in rats with metaflammation model

为了探讨胆酸对代谢性炎症模型大鼠炎症的影响,揭示其调控机理,从而为宠物新型抗代谢性炎症药物的研究提供试验基础,试验用饲喂高脂饲料60 d的SD大鼠建立代谢性炎症模型。将大鼠随机分为5组,即模型组,胆酸高、中、低剂量组,阴性对照组,连续灌胃给药30 d后处死大鼠,采用HE染色法,观察肝脏组织病理学变化;采用ELISA试剂盒检测单核细胞趋化因子1(MCP-1)、白介素6(IL-6)、白介素1β(IL-1β)的含量;采用实时荧光定量PCR法检测巨噬细胞炎性蛋白1α(MIP-1α)、白介素10(IL-10)、白介素8(IL-8)、肿瘤坏死因子(TNF-α)表达量;采用免疫组化法检测过氧化物酶体增殖物激活受体α(PPARα)及肝X受体α(LXRα)的分布及表达。结果显示,与阴性对照组相比,模型组大鼠的肝脏组织中出现脂肪空泡以及以巨噬细胞为主的炎性细胞聚集;而给予胆酸治疗的高、中、低剂量组大鼠的肝脏细胞中细胞形态和大小均正常,且炎性细胞减少以及脂肪蓄积得到改善。与阴性对照组相比,模型组的MIP-1α及IL-8的表达量极显著升高(P<0.01),MCP-1的含量、TNF-α的表达量显著升高(P<0.05);与模型组相比,胆酸高剂量组MIP-1α、IL-10及IL-8表达量极显著降低(P<0.01),胆酸中、低剂量组的IL-10表达量显著降低(P<0.05),MIP-1α及IL-8表达量极显著降低(P<0.01),胆酸中剂量组的TNF-α的表达量显著降低(P<0.05)。PPARα及LXRα受体均分布在肝脏细胞核,模型组PPARα表达量较阴性对照组极显著下降(P<0.01),胆酸高、中剂量组PPARα表达量较模型组极显著上调(P<0.01)、低剂量组显著上调(P<0.05),胆酸高、中、低剂量组较模型组LXRα表达量极显著下调(P<0.01)。结果表明,胆酸能够通过上调PPARα、下调LXRα的表达,抑制脂肪生成,从而降低代谢性炎症模型大鼠的炎症反应。

To investigate the effects of cholic acid on inflammation in rats with metaflammation,and to reveal the regulatory mechanism of cholic acid on metaflammation,so as to provide experimental basis for the study of new drugs to prevent and treat of metaflammation for pets.The metaflammation model was established in SD rats fed high-fat diet for 60 days.The rats were randomly divided into five groups:model group,high-dose,medium-dose and low-dose cholic acid group and negative control group.After continuous intragastric administration for 30 days,the rats were killed.The liver tissue sections were stained with HE to observe the histopathological changes of liver;monocyte chemokine-1(MCP-1),interleukin-6(IL-6) and interleukin-1β(IL-1β) were detected by ELISA;macrophage inflammatory protein 1α(MIP-1α),interleukin-10(IL-10),interleukin-8(IL-8) and tumor necrosis factor(TNF-α) were detected by real-time fluorescence quantitative PCR;distribution and expression of the peroxidase extracted proliferator activated receptor a(PPARa) and the liver X receptor α(LXRα) were detected by immunohistochemistry.The results showed that the cell morphology and size of liver cells in high-dose,medium-dose and low dose group treated with cholic acid were normal and the inflammatory cells decreased and the fat accumulation were improved based on the HE staining section of liver.Compared with the negative control group,the MCP-1 content,MIP-1α,IL-8 and TNF-α expression of the model group were significantly increased;compared with the model group,MIP-1α,IL-10 and IL-8 expression of the high-dose group were significantly decreased;the expression of IL-10,MIP-1α and IL-8 in the middle and low dose groups were significantly decreased;the expression of TNF-α in the middle dose group were significantly decreased.PPARα and LXRα receptors were distributed in the nuclei of liver.The expression of PPAR a in model group was significantly lower than that in negative control group.The expression of PPAR a in high and medium dose groups was significantly higher than that in model group.The expression of PPAR a in low dose groups was significantly higher than that in model group.The expression of LXRα in high,medium and low dose groups was significantly lower than that in model group.Cholic acid can inhibit adipogenesis and reduce the inflammatory response of metabolic inflammation model rats by up-regulating PPARα and downregulating of LXRα expression.