Department of Health Toxicology, School of Public Health, Guilin Medical University, 109 Huancheng North Road 2, Guilin, Guangxi, 541004, People's Republic of China.
Biol Trace Elem Res. 2020 Nov;198(1):224-230. doi: 10.1007/s12011-020-02067-1. Epub 2020 Feb 25.
As an essential trace element in the human body, manganese (Mn) is involved in many important biochemical reactions. However, excessive exposure to manganese can cause multiple systematic damages to the body. This study aims to investigate the effects of manganese exposure on serum hepatic enzymes in male rats at different time points. After adaptive feeding for 7 days, male Sprague-Dawley (SD) rats were injected intraperitoneally with 30 mg/kg MnCl·4HO once a day for 21 days at zeitgeber time point 2 (ZT2), ZT8, ZT14, and ZT20, respectively. We found that short-term repeated exposure to manganese caused slower body weight gain and increased relative liver and spleen weight index in male rats at different time points. Moreover, serum total bile acid (TBA) increased while aspartate aminotransferase (AST) decreased at ZT2, ZT8, and ZT20. Cholinesterase (ChE) decreased at ZT2 and ZT20, lactic dehydrogenase (LDH) decreased at ZT2, ZT14, and ZT20, and acid phosphatase (ACP) decreased at ZT2 and ZT14. Alkaline phosphatase (ALP) decreased at ZT2, ZT14, and ZT20, but increased at ZT8. Alanine amino transferase (ALT) decreased at ZT2 and ZT20, but increased at ZT8. There was a negative correlation between relative liver weight index with AST, ACP, ALP, and LDH, while a positive correlation with TBA. However, relative spleen weight index had a positive correlation with relative liver weight index and TBA, while a negative correlation with ALT, AST, ACP, ALP, LDH, and ChE. Our study shows that the injury of liver function is caused by short-term repeated manganese exposure at different time points. The time effect should be considered in manganese toxicity evaluation.
作为人体必需的微量元素，锰（Mn）参与许多重要的生化反应。然而，过量接触锰会对身体造成多种系统性损伤。本研究旨在探讨不同时间点腹腔注射 MnCl·4HO 对雄性大鼠血清肝酶的影响。雄性 Sprague-Dawley（SD）大鼠适应性喂养 7 天后，分别在 Zeitgeber 时间点 2（ZT2）、ZT8、ZT14 和 ZT20 时，每天腹腔注射 30mg/kg MnCl·4HO 一次，连续 21 天。结果发现，短期重复接触锰会导致雄性大鼠在不同时间点体重增长缓慢，肝脾相对重量指数增加。此外，血清总胆汁酸（TBA）在 ZT2、ZT8 和 ZT20 时升高，天冬氨酸氨基转移酶（AST）降低；胆碱酯酶（ChE）在 ZT2 和 ZT20 时降低，乳酸脱氢酶（LDH）在 ZT2、ZT14 和 ZT20 时降低，酸性磷酸酶（ACP）在 ZT2 和 ZT14 时降低，碱性磷酸酶（ALP）在 ZT2、ZT14 和 ZT20 时降低，ZT8 时升高；丙氨酸氨基转移酶（ALT）在 ZT2 和 ZT20 时降低，ZT8 时升高。肝相对重量指数与 AST、ACP、ALP 和 LDH 呈负相关，与 TBA 呈正相关；而脾相对重量指数与肝相对重量指数和 TBA 呈正相关，与 ALT、AST、ACP、ALP、LDH 和 ChE 呈负相关。本研究表明，不同时间点短期重复锰暴露会导致肝功能损伤，在锰毒性评价中应考虑时间效应。
