Mruk D D, Cheng C Y
Population Council, Center for Biomedical Research, New York, New York, USA.
Life Sci. 2000;67(2):133-45. doi: 10.1016/s0024-3205(00)00609-3.
Rat Sertoli and germ cells express extracellular superoxide dismutase (SOD(EX)), however, the relative level of SOD(EX) expressed by these cells was not known. We report herein germ cells consisting largely of spermatogonia, spermatocytes, and round spermatids expressed only one-third SOD(EX) as that of Sertoli cells when examined by semi-quantitative RT-PCR. While cocultures of germ cells with Sertoli cells failed to induce any changes in SOD(EX) expression possibly due to the limited number of cells that can be supported by the in vitro culture system dissimilar to the in vivo condition, incubation of total germ cell-conditioned medium with Sertoli cells was able to significantly inhibit Sertoli cell SOD(EX) expression dose-dependently suggesting a germ cell-derived soluble factor(s) may regulate SOD(EX) in the testis. On the other hand, cytokines such as TGF-beta1, beta-NGF, or FGF and steroid hormones such as estradiol-17beta, progesterone, testosterone, and DHT were unable to effect the expression of Sertoli cell SOD(EX). However, FSH at 100 ng/dish was able to induce a significant increase in Sertoli cell SOD(EX) expression. While cytokines, the known mediators of the inflammatory response, were unable to affect Sertoli cell SOD(EX) expression, the induction of generalized inflammation in vivo was able to cause a 2- to 2.5-fold increase in testicular SOD(EX) expression concomitant with a transient increase in the liver but not in the brain. Taken collectively, these results demonstrate that while SOD(EX) is an important antioxidant enzyme protecting the testis from reactive oxygen species, the mechanism(s) regulating its expression may involve an array of molecules and is a complicated cellular event.
大鼠支持细胞和生殖细胞表达细胞外超氧化物歧化酶（SOD(EX)），然而，这些细胞所表达的SOD(EX)的相对水平尚不清楚。我们在此报告，通过半定量逆转录聚合酶链反应检测发现，主要由精原细胞、精母细胞和圆形精子细胞组成的生殖细胞所表达的SOD(EX)仅为支持细胞的三分之一。虽然生殖细胞与支持细胞共培养未能诱导SOD(EX)表达发生任何变化，这可能是由于体外培养系统与体内条件不同，所能支持的细胞数量有限，但用总生殖细胞条件培养基孵育支持细胞能够显著剂量依赖性地抑制支持细胞SOD(EX)的表达，这表明生殖细胞衍生的一种或多种可溶性因子可能在睾丸中调节SOD(EX)。另一方面，细胞因子如转化生长因子-β1、β-神经生长因子或成纤维细胞生长因子以及类固醇激素如雌二醇-17β、孕酮、睾酮和双氢睾酮均不能影响支持细胞SOD(EX)的表达。然而，每培养皿100纳克的促卵泡激素能够诱导支持细胞SOD(EX)表达显著增加。虽然细胞因子作为炎症反应的已知介质不能影响支持细胞SOD(EX)的表达，但体内全身性炎症的诱导能够使睾丸SOD(EX)表达增加2至2.5倍，同时肝脏中短暂增加，但大脑中没有增加。综合来看，这些结果表明，虽然SOD(EX)是一种重要的抗氧化酶，可保护睾丸免受活性氧的损伤，但其表达的调节机制可能涉及一系列分子，是一个复杂的细胞事件。
