Monocyte chemoattractant protein-1(MCP-1) is a chemokine secreted by Leydig cells and peritubular myoid cells in the rat testis. Its role in regulating the development of Leydig cells via autocrine and paracrine is still unclear. The objective of the current study was to investigate the effects of MCP-1 on Leydig cell regeneration from stem cells in vivo and on Leydig cell development in vitro. Intratesticular injection of MCP-1(10 ng/testis) into Leydig cell-depleted rat testis from post-EDS day 14 to 28 significantly increased serum testosterone and luteinizing hormone levels, up-regulated the expression of Leydig cell proteins, LHCGR, SCARB1, CYP11A1, HSD3B1, CYP17A1, and HSD17B3 without affecting progenitor Leydig cell proliferation, as well as increased ERK1/2 phosphorylation. MCP-1 (100 ng/ml) significantly increased medium testosterone levels and up-regulated LHCGR, CYP11A1, and HSD3B1 expression without affecting EdU incorporation into stem cells after in vitro culture for 7 days. RS102895, a CCR2 inhibitor, reversed MCP-1-mediated increase of testosterone level after culture in combination with MCP-1. MCP-1 stimulates the differentiation of stem and progenitor Leydig cells without affecting their proliferation.

中文翻译：

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单核细胞趋化蛋白-1 在再生过程中刺激大鼠干细胞和祖细胞间质细胞的分化

单核细胞趋化蛋白-1(MCP-1) 是一种由大鼠睾丸间质细胞和管周肌样细胞分泌的趋化因子。其通过自分泌和旁分泌调节 Leydig 细胞发育的作用尚不清楚。当前研究的目的是研究 MCP-1 对体内干细胞 Leydig 细胞再生和体外 Leydig 细胞发育的影响。从 EDS 后第 14 天至第 28 天，将 MCP-1（10 ng/睾丸）睾丸内注射到 Leydig 细胞耗尽的大鼠睾丸中，可显着增加血清睾酮和黄体生成素水平，上调 Leydig 细胞蛋白、LHCGR、SCARB1、 CYP11A1、HSD3B1、CYP17A1 和 HSD17B3 不影响祖细胞 Leydig 增殖，以及增加 ERK1/2 磷酸化。在体外培养 7 天后，MCP-1 (100 ng/ml) 显着增加培养基睾酮水平并上调 LHCGR、CYP11A1 和 HSD3B1 表达，而不影响 EdU 掺入干细胞。RS102895 是一种 CCR2 抑制剂，与 MCP-1 联合培养后，可逆转 MCP-1 介导的睾酮水平升高。MCP-1 刺激干细胞和祖细胞 Leydig 细胞的分化而不影响它们的增殖。