小剂量左卡尼汀对模拟高原环境急性暴露期内雄性Wistar大鼠生殖功能的保护作用

The protective effect of low-dose L-carnitine on the reproductive function of male Wistar rats during acute exposure to simulated high-altitude environment

摘要

目的：探讨小剂量左卡尼汀（L-Carnitine,LC）对模拟高原环境下急性暴露期内雄性Wistar大鼠生殖系统损害的干预保护作用。方法：选取12周龄SPF级雄性Wistar大鼠24只，随机分为空白对照组、高原模型组和LC干预组[腹腔注射左卡尼汀50 mg/（kg·d）]，每组8只。空白对照组常规条件（海拔约1 500 m）饲养，高原模型组饲养和LC干预组低压氧舱内（模拟海拔6 000 m）饲养。3 d后处死，取睾丸计算睾丸指数，取大鼠附睾中精液，采用伟力数码彩色精子质量检测系统测定精子质量，取腹主动脉血采用Elisa生化试剂盒测定血清性激素睾酮（testosterone,T）、黄体生成素（luteinizing hormone,LH）、促卵泡激素（follicle-stimulating hormone,FSH）水平，取睾丸组织采用生化试剂盒测定睾丸活性氧（reactive oxygen species,ROS）、丙二醛（malondialdehyde,MDA）、超氧化物歧化酶（superoxide dismutase,SOD）活性指标，取睾丸组织制备苏木精-伊红染色（hematoxylin and eosin staining,HE）、电镜切片进行光镜、透射电镜观察。结果：与空白对照组相比，高原模型组T、LH、FSH水平明显升高（P<0.01），光镜观察可见睾丸组织损伤，电镜观察生精细胞内线粒体形态改变，膜水肿、嵴出现缺失，基质肿胀、局部溶解，ROS、MDA水平明显升高（P<0.01）,SOD活性明显降低（P<0.01）；与高原模型组相比，LC干预组T水平明显升高（P<0.01）,FSH、LH水平明显下降（P<0.01），睾丸组织损伤病理改变明显改善，线粒体未发生明显损伤、ROS、MDA水平明显降低（P<0.01）,SOD的活性明显升高（P<0.01）。各组睾丸指数差异无统计学意义（P>0.05）。高原模型组精子数量明显低于空白对照组（P<0.05），而LC干预组与空白对照组之间精子数量差异无统计学意义（P>0.05）；各组精子活动率差异无统计学意义（P>0.05）。结论：小剂量左卡尼汀可以改善模拟高原环境急性暴露对大鼠生殖系统的损伤，其机制可能与减轻氧化应激反应有关。

Abstract

Objective To investigate the interventional and protective effect of low-dose L-carnitine（LC） against reproductive system damage in male Wistar rats during acute exposure to simulated high-altitude environment. Methods A total of 24 specific pathogen-free male Wistar rats，aged 12 weeks，were randomly divided into control group，high-altitude model group，and LC intervention group ［intraperitoneal injection of LC at a dose of 50 mg/（kg·d）］，with 8 rats in each group. The rats in the control group were fed under normal conditions（at an altitude of approximately 1 500 m），those in the high-altitude model group，and those in the LC intervention group were fed in a hypobaric oxygen chamber（at a simulated altitude of 6 000 m）. The rats were sacrificed after 3 days. The testis was collected to calculate testicular index；the semen was collected from the epididymis，and the Weili sperm quality analysis system was used to assess sperm quality；blood samples were collected from the abdominal aorta，and ELISA kits were used to measure the serum levels of testosterone（T），luteinizing hormone（LH），and follicle-stimulating hormone（FSH）；testicular tissue samples were collected，and biochemical kits were used to measure the activity of reactive oxygen species（ROS），malondialdehyde（MDA），and superoxide dismutase（SOD）；testicular tissue was collected to prepare HE and electron microscopy sections，and a light microscope and a transmission electron microscope were used for observation. Results Compared with the blank control group，the high-altitude model group had significant increases in the levels of T，LH，and FSH（P<0.01），testicular tissue damage under the light microscope，and changes in the morphology of spermatogenic cells，including mitochondrial alterations，membrane edema，loss of cristae，swelling of the matrix，and local dissolution，as well as significant increases in the levels of ROS and MDA（P<0.01） and a significant reduction in SOD activity（P<0.01）. Compared with the high-altitude model group，the LC intervention group had a significant increase in the level of T（P<0.01），significant reductions in the levels of FSH and LH（P<0.01），and significant improvements in the pathological changes of testicular tissue，with no marked mitochondrial injury，and there were significant reductions in the levels of ROS and MDA（P<0.01） and a significant increase in SOD activity（P<0.01）. There was no significant difference in testicular index between groups（P>0.05）. The high-altitude model group had a significantly lower sperm count than the blank control group（P<0.05），while there was no significant difference in sperm count between the LC intervention group and the blank control group（P>0.05）；there was no significant difference in sperm motility between groups（P>0.05）. Conclusion Low-dose LC can improve reproductive system damage in rats during acute exposure to simulated high-altitude environment，possibly by alleviating oxidative stress response.

关键词

高原缺氧 / 左卡尼汀 / 雄性 / 生殖

Key words

plateau hypoxia / L-carnitine / male / reproduction

基金资助

甘肃省自然科学基金资助项目(22JR5RA001;23JRRA531)

2024年度中央高校基本科研业务费专项资金资助项目(31920240072)

兰州市科技计划资助项目(2023-2-63)