低硒饮食对大鼠肝肾中CD163、CD206、CCR7表达的影响

目的探讨低硒饮食对大鼠肝肾的影响，以及巨噬细胞向M1、M2的极化在肝肾纤维化中的作用。方法利用低硒和正常 饲料分别喂养大鼠，建立低硒动物模型。将12 只雌性与12 只雄性SD大鼠按随机数字表法分成2 组：对照组（Z组，饲料硒 0.18 mg/kg）、低硒组（S组，饲料硒0.02 mg/kg），饲养109 d后处死大鼠，HE染色观察肝肾病理改变，免疫组化采用SP法染色检 测肝肾组织中CCR7、CD206、CD163阳性细胞数量。结果（1）低硒组大鼠肝肾纤维化较对照组严重；（2）雌雄大鼠肝脏低硒组 CCR7、CD206染色强度与对照组（雌性、雄性、雌性、雄性，P均>0.05）相比较均无统计学差异。CD163染色强度低于对照组（雌 性、雄性P均<0.05），有统计学意义；（3）雌雄大鼠肾脏低硒组CCR7染色强度在近球小管略高于对照组（雌性、雄性P均>0.05）， 在远球小管中略低于对照组（雌性P>0.05、雄性P<0.05），然而结果均无统计学差异；CD163染色强度在远球小管中低于对照组 （雌性、雄性P均<0.05），CD206染色强度在近球小管中高于对照组（雌性P、雄性P均<0.05），有统计学意义；CD163染色强度在 近球小管中低于对照组（雌性P>0.05、雄性P<0.05），雌性无统计学意义，雄性有统计学意义，CD206染色强度在远球小管中高 于对照组（雌性P<0.05、雄性P>0.05），雌性有统计学意义，雄性无统计学意义。结论低硒组大鼠肝肾出现了明显的纤维化，同 时低硒可能抑制巨噬细胞向M2型极化。

Effect of low-selenium diet on expressions of CCR7, CD206 and CD163 in the liver and kidney of rats

Objective To investigate the effect of low-selenium diet on the liver and kidneys of rats and explore the role of macrophage polarization into M1 and M2 phenotypes in liver and kidney injuries. Methods Twenty-four rats (12 female and 12 male) were randomly divided into control group and low-selenium group and fed with normal chow (dietary selenium of 0.18 mg/kg) and low-selenium diet (dietary selenium of 0.02 mg/kg) for 109 days. After the feeding, the rats were sacrificed for HE staining to observe liver and kidney pathologies, and immunohistochemistry was performed for analyzing CCR7, CD206, CD163-positive cell numbers in the liver and kidneys. Results The rats in low-selenium group showed severer fibrosis in the liver and kidney than the control group. In either male or female rats in low-selenium group, CCR7 and CD206 expressions in the liver were comparable with those in control group, but CD163 expression was lower than that in the control group (P<0.05 for both female and male rats). In the kidney, the proximal tubule showed a slightly higher while the distal tubule showed a slightly lower CCR7 expression in low selenium group than in the control group (P>0.05). In low-selenium group, a significantly lower CD163 expression in the distal tubule and a significantly higher CD206 expression in the proximal tubule were noted as compared with the control group (P<0.05 in both female and male rats). Compared with the control rats, the male rats in low-selenium group, but not the female rats, showed a significantly lower CD163 expression in the proximal tubule of the kidney (P<0.05);the female but not the male rats in low-selenium group show a higher CD206 expression in the distal tubule (P<0.05). Conclusion Low-selenium diet can cause liver and kidney fibrosis in rats and may inhibit macrophage activation into the M2 phenotype.