Liver Function of Male Rats Exposed to Manganese at Different Time Points.

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 MnCl2·4H2O 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.

The early toxic effect sensitive index of short-term-repeated exposure to cadmium chloride in male rats / 中国职业医学

OBJECTIVE: To observe the early adverse effect index caused by short-term-repeated exposure to cadmium chloride via oral perfusion in male rats. METHODS: Forty specific pathogen free healthy male SD rats were randomly divided into four groups: control group,low-,middle-and high-dose groups. The rats of low-,middle-and high-dose groups were treated with cadmium chloride 1. 11,3. 51 and 11. 06 mg/kg body weight,respectively,and the control group rats was treated with the same volume of ultra pure water,by gavage once a day for four weeks. During the experimental duration,the body weights of the rats were taken and activity status of the rats was observed. After the experiment,the rats were executed,and some indicators of main organ coefficients,blood routine,serum biochemical indexes,urine related effect indexes and bone mineral density were measured. RESULTS: During the experimental duration,rats of high-dose group showed the symptoms such as decreased activity,increase repose,move slowly and skin duller. Comparing with control group at the same time points,the body masses of the high-dose group of the 1-4 weeks were lower(P < 0. 05).After the experiment,comparing with control group,the weights of kidney and spleen of the high-dose group decreased significantly(P < 0. 05) and the liver coefficient increased significantly(P < 0. 05). The cadmium levels in blood,urine,liver,kidney and thighbone of the middle-and high-dose groups were higher than those of the control group(P < 0. 05).The red blood cell counts of the low-and middle-dose groups increased significantly(P < 0. 05). The level of hemoglobin of middle-and high-dose groups decreased(P < 0. 05),and the activity of alanine aminotransferase in high-dose groups increased significantly(P < 0. 05). Comparing with control group,the levels of urine α_1-microglobulin and urine β_2-microglobulin in urine of the middle-dose group were decreased(P < 0. 05) and the level of urine urea nitrogen increased(P < 0. 05),but there were no significantly changes of the above three indexes in the high-dose group(P >0. 05). There were no significant difference of the levels of N-acetyl-beta-D glucosaminidase in urine between control and treatment groups(P > 0. 05). Simultaneously,in high-dose group,the weight of thighbone,the bone calcium content and bone mineral density reduced significantly than those of the control group(P < 0. 05). CONCLUSION: Skeletal effects can be used as an early toxic effect sensitive index of short-term-repeated experiments exposure to cadmium chloride via oral perfusion in male rats.