RESUMO
Objective To study the effect of metabolic syndrome on the fertility and reproduction in model animals. Methods The model of"high fat diet for spontaneously hypertensive rats(SHR)"was adopted to construct the model of metabolic syndrome in rats. The metabolic syndrome model rats were used to mate with male and female 1 : 1 cage, and the mating cycle was 2 weeks. Results After the SHR rats were fed a high-fat diet for 10 weeks, 16 males and 15 females met the screening criteria for metabolic syndrome, with the modeling rates of 40% and 37.5%, respectively. In addition to the abnormal metabolism-related indicators(such as blood glucose, blood lipid and blood pressure), the male rats with metabolic syndrome mainly had decreased sperm motility(P < 0.05), increased sperm malformation rate(P < 0.01), and decreased mating rate(P < 0.05). In addition to abnormal metabolism-related indicators, the conception rate and the live fetal rate of the female rats with metabolic syndrome were slightly lower than that of the control group; however, there was no statistical difference. The mean birth weight of the litter was significantly lower than that of the control group(P < 0.05). Conclusion According to the whole process from mating to natural production, metabolic syndrome is determined to have a significant effect on the fertility and reproductive ability of rats.
RESUMO
Objective:To establish a comet test method for detection of genotoxicity of three reference chemicals in rat liver cells. Methods:6-10 week old Sprague Dawley rats were randomly divided into 4 groups， with normal saline （0.9% NaCl solution） as negative control group. Animals in three test groups were treated， respectively， with ethyl methanesulfonate （EMS） 200 mg/kg， N-methyl-N-nitrosourea （MNU） 50 mg/kg， and D-mannitol 2 000 mg/kg. There were 10 animals in each group， 5 males and 5 females. The animals received two times （21 h interval） of test compounds through intragastric administration， and their clinical symptoms and body weight changes were recorded during the experiment. The rats were sacrificed 3 h after the last exposure. The liver was weighed， then used to prepare single-cell suspensions for the alkaline comet test which determines the average tail DNA content percentage （DNA%） of hepatocytes and other comet indicators. Results:（1） D-mannitol， EMS and MNU did not show significant toxicity in the whole animal. （2） The mean values of tail DNA content percentage （DNA%） of rat hepatocytes in EMS ［（60.07±24.69）%］ and MNU ［（41.66±22.35）%］ groups were higher than that in the negative control group ［（2.32±1.39）%］ and the difference was statistically significant （P<0.05）. The difference between D-mannitol group ［（3.06±3.30）%］ and the negative control group was not significant （P>0.05）. Conclusion:This laboratory has established a comet test method using hepatocytes from treated rats. Among three testing chemicals， EMS and MNU have displayed genotoxicity by this assay， but no genotoxicity was observed in D-mannitol treated animals.