低硒饮食对大鼠肝肾中CD163、CD206、CCR7表达的影响

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

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。

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 and12 male) were randomly divided into control group and low-selenium group and fed with normal chow(dietary selenium of0.18 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.