| BackgrouedEthephon（2-chloroethyl phosphonic acid）,as an organic phosphorus ripening agent,is widely used to shorten the cultivation time of crops and accelerate the ripening process.Excessive use will lead to its residue on the surface of fruits and vegetables,and eating by mistake will affect the health of the body.Song Cuiping and other scholars have shown that ethephon can promote the apoptosis of spermatogenic cells and has certain reproductive toxicity.However,there are few studies on oligozoospermia and asthenospermia in rats caused by Ethephon.Therefore,this experiment exposed male SD rats to different concentrations of ethephon,observed the pathological changes of testis and epididymis,detected the changes of oxidative stress and energy metabolism in testis and epididymis,and discussed the effect of ethephon exposure on sperm quality and possible mechanism.ObjectivesTo investigate the effects of ethephon exposure on the histopathology and sperm quality of testis and epididymis of adolescent male SD rats.MethodsForty sound male SD rats aged 45 days were stochastically divided into four groups according to the random number table method:the control group and the low,medium and high experimental groups.The rats were given 0.9%normal saline and 100 mg/kg,200mg/kg and 400 mg/kg ethephon aqueous solution every day for 28 days.24 hours after the last gavage,the rats were weighed and anesthetized with 10%chloral hydrate（0.7 m L/100 g）.After anesthesia,the rats were killed.The left epididymal tail of rats was taken,washed with normal saline and prepared sperm suspension,and the sperm concentration and motility were detected;The right testis and epididymis were fixed,dehydrated and stained with he.The pathological changes of testis and epididymis were observed under light microscope;Take 0.1～0.2 g of testicular and epididymal tissue blocks to wash away the blood stain,prepare tissue homogenate,and detect the activities of acid phosphatase（ACP）,lactate dehydrogenase（LDH）and succinate dehydrogenase（SDH）,superoxide dismutase（SOD）,glutathione peroxidase（GSH-PX）and malondialdehyde（MAD）in testis and epididymis;The levels of Nrf2 protein in testis,a-glucosidase activity in epididymis,L-carnitine（LC）content,Nrf2 protein and OCTN2 protein expression were detected by ELISA kit to evaluate the effects of Ethephon on energy metabolism and oxidative damage of testis and epididymis.ResultsThe sperm concentrations（10~6/ml）of control group,low,medium and high ethephon exposed rats were 40.21±1.94,35.23±2.53,23.61±2.62 and 18.86±2.16 respectively;The activity rates（%）were 70.98±3.01,57.96±3.75,45.71±2.41 and 31.23±2.26respectively;The sperm concentration and motility in the experimental group were significantly lower than those in the control group（P<0.01）;In the control group,the ACP activity of testis in low,medium and high experimental groups（U/g）:86.12±3.48,76.29±2.53,63.21±2.53,55.65±2.81;LDH activity（U/mg）:9.73±0.81,8.16±0.43,7.12±0.53,6.01±0.36;SDH activity（U/g）:7.48±0.41,6.30±0.42,5.61±0.25,4.96±0.19;The enzyme activities of ACP/LDH and SDH in the experimental group were significantly lower than those in the control group（P<0.05）.In the control group,the activity of SOD in testis of rats in low,medium and high experimental groups（U/mg prot）:48.29±2.60,41.48±2.26,33.29±2.40,26.58±2.45;GSH-PX activity（U/mg prot）:23.64±1.73,20.84±1.13,17.11±1.66,15.61±1.56;MDA content（n mol/mg）:1.39±0.054,1.53±0.071,1.73±0.071,1.99±0.107;Nrf2 protein level（pg/ml）:1.34±0.048,1.25±0.042,1.08±0.055,0.92±0.039;Compared with the control group,the activities of SOD and GSH-PX enzyme in the testis of the experimental group decreased significantly（P<0.05）,the amount of MDA increased significantly（P<0.05）,and the expression level of Nrf2 in the experimental group decreased significantly（P<0.05）.SOD activity in rat epididymis（U/mg）:46.48±2.21,38.49±2.56,33.80±1.73,27.65±2.05;GSH PX activity（U/mg）:21.41±1.95,17.32±1.28,15.09±0.94,14.08±1.23;MDA content（n mol/mg）:1.41±0.088,1.59±0.089,1.81±0.087,2.16±0.137;Nrf2 protein level（pg/ml）:1.47±0.016,1.16±0.013,0.97±0.018,0.82±0.011;The activities of SOD and GSH PX in the epididymis of the experimental group were significantly lower than those of the control group（P<0.05）,while the content of MDA was significantly higher than that of the control group（P<0.05）.The expression level of Nrf2 in the experimental group was significantly lower than that of the control group（P<0.01）.Epididymal a-glucosidase（U/ml prot）of rats in control group,low,medium and high experimental groups:15.79±0.71,12.94±0.72,11.15±0.69 and 10.03±0.44;Levocarnitine（ng/ml）:6.20±0.31,5.89±0.13,5.01±0.12,4.37±0.07,OCTN2 protein level（pg/ml）:4.55±0.13,4.23±0.11,3.20±0.24,2.59±0.05;Compared with the control group,the concentrations of a-glucosidase and LC in the experimental group decreased significantly（P<0.01）;The expression level of OCTN2 in ethephon experimental group was significantly lower than that in control group（P<0.01）.ConclusionExposure to excessive doses of ethephon causes excessive ROS in rat reproductive organs,leading to oxidative stress.It may reduce the number,vitality and quality of rat sperm by activating keap1-Nrf2/ARE signal pathway,resulting in the impairment of their fertility. |
PDF Full Text Request