Zini A, Schlegel P N
James Buchanan Brady Foundation, Department of Urology, New York Hospital-Cornell Medical Center, New York 10021, USA.
J Androl. 1996 Sep-Oct;17(5):473-80.
Reactive oxygen species (ROS) have been shown to impair sperm function. The actions of ROS are reduced by antioxidant enzymes, including catalase. Although catalase-like activity has been demonstrated in semen, there has been no localization or characterization of catalase mRNA expression in the male reproductive tract. Catalase mRNA levels were evaluated by northern blot analysis and in situ hybridization from the male reproductive organs of normal 60-day-old rats, testes of 10- to 90-day-old rats, and testes of rats subjected to efferent duct ligation. Radioactive DNA probes were synthesized using a Klenow polymerase-based specific primer synthetic procedure with a known published sequence for rat catalase. All tissues demonstrated a single transcript of 2.5 kilobases (kb). Low levels of catalase mRNA were detected in the normal testis, epididymis, vas deferens, and prostate. No expression was detectable with northern analysis in seminal vesicle. The levels of catalase mRNA in reproductive organs were compared with the high levels of expression detectable in rat liver. In the testis, catalase expression was primarily localized to peritubular and interstitial cells. In the epididymis and prostate, mRNA was detected in the epithelium. The observed decrease in catalase mRNA levels in the maturing rat testis is consistent with its interstitial localization. The increase in testicular catalase mRNA levels seen in parallel with progressive thinning of the germinal epithelium after efferent duct ligation is also in keeping with a peritubular or interstitial cell localization. The relatively low levels of catalase mRNA expression in the normal adult male reproductive tract undermine the role of catalase as a major antioxidant enzyme in these tissues. The low levels of catalase mRNA in the testis, and the undetectable levels in the seminiferous epithelium, however, imply that the germinal epithelium is predisposed to an oxidative state. These findings may help to explain the known susceptibility of the testis to oxidative stress.
活性氧（ROS）已被证明会损害精子功能。抗氧化酶（包括过氧化氢酶）可降低ROS的作用。虽然精液中已证实存在类似过氧化氢酶的活性，但雄性生殖道中过氧化氢酶mRNA表达的定位或特性尚未明确。通过Northern印迹分析和原位杂交，对60日龄正常大鼠的雄性生殖器官、10至90日龄大鼠的睾丸以及进行了输出小管结扎的大鼠睾丸中的过氧化氢酶mRNA水平进行了评估。使用基于Klenow聚合酶的特异性引物合成程序，根据已发表的大鼠过氧化氢酶已知序列合成放射性DNA探针。所有组织均显示出一条2.5千碱基（kb）的单一转录本。在正常睾丸、附睾、输精管和前列腺中检测到低水平的过氧化氢酶mRNA。精囊经Northern分析未检测到表达。将生殖器官中过氧化氢酶mRNA的水平与大鼠肝脏中可检测到的高水平表达进行了比较。在睾丸中，过氧化氢酶表达主要定位于生精小管周围细胞和间质细胞。在附睾和前列腺中，上皮细胞中检测到mRNA。在成熟大鼠睾丸中观察到的过氧化氢酶mRNA水平下降与其间质定位一致。输出小管结扎后，随着生精上皮逐渐变薄，睾丸过氧化氢酶mRNA水平升高，这也与定位在生精小管周围或间质细胞一致。正常成年雄性生殖道中过氧化氢酶mRNA表达水平相对较低，这削弱了过氧化氢酶作为这些组织中主要抗氧化酶的作用。然而，睾丸中过氧化氢酶mRNA水平较低，而生精上皮中未检测到，这意味着生精上皮易处于氧化状态。这些发现可能有助于解释睾丸对氧化应激已知的易感性。
