| Cadmium(Cd)is a widely used heavy metal pollutant,which is widely used in batteries,coatings,plastics,smelting and electroplating.Its half-life is long.After it accumulates in the environment,it will enter the food chain and cause damage to multiple organs of humans and animals through biological amplification and accumulation.Testis is one of the important target organs of its toxicity.Selenium(Se)is an essential trace element in vivo and has obvious antagonistic effect against Cd.However,the mechanism by which Se alleviates Cd in chicken testis injury through oxidative stress,endoplasmic reticulum stress and programmed necrosis remains unclear.In this study,the reproductive toxicity of Cd and the mechanism of Se against Cd reproductive toxicity were enriched to provide a new idea for prevention and treatment of Cdinduced testicular injury.Eighty 7-day-old Hyline chickens were randomly divided into the control group,Se group(1.00 mg/kg Se),Cd group(150.00 mg/kg Cd)and Cd-Se co-treated group(150.00 mg/kg Cd;1.00mg/kg Se).On the 30 th and 60 th days of feeding,10 chickens were randomly selected from each group,weighed,blood was drawn,and testicles were collected and weighed.After separating plasma,the testosterone content was detected by ELISA.After HE staining,the testicular tissue structure was observed under microscope.The contents of Cd and Se in the samples were determined by ICP-MS.ROS levels in testis were detected by DCFH-DA fluorescent probe.The activities of MDA,GSH,GSH-Px,CAT and SOD in testis were determined by spectrophotometry.The m RNA and protein expression levels of GRP78,PERK,IRE1,ATF6,CHOP,JNK,TNF-α,TNFR1,RIP1,RIP3,MLKL,PARP1 and Caspase-8 were detected by fluorescence quantitative PCR and Western-blot.The experimental results are as follows:1.Chickens in the Cd group showed depression,loss of appetite and disordered feathers,and their body weight was significantly lower than that in the normal control group(P<0.05).The testis volume of Cd group was significantly lower than that of normal control group,and the testicular coefficient of Cd group was significantly different from that of normal group(P<0.05).The mental state and appetite of chickens in the co-treated group were significantly higher than those in the Cd group.The body weight of chickens in the co-treated group was higher than that in the Cd group(P<0.05),but less than that in the normal group.Testicular coefficient at 30 days of age was not significantly different from that of Cd group,but was significantly higher than that of Cd group at60 days of age(P<0.05).2.Obvious Cd accumulation occurred in the Cd group,and the Cd accumulation in the Cd-Se co-treatment group was significantly lower than that in the Cd group(P<0.05).3.In the Cd group,the seminiferous tubules were swollen and deformed,the spermatogenic epithelium became thinner,the contents fell off,and vacuoles appeared.In the Cd-Se group the tubule swelling was significantly improved,the interstitial thickened,and the number of spermatogenic epithelial cell layers increased.But there was a gap with the control group.The results of blood testosterone level showed that the blood testosterone level of Cd group was significantly lower than that of control group(P<0.05),and that of Cd-Se group was significantly higher than that of Cd group(P<0.05).4.The ROS level in Cd group was significantly increased compared with control group(P<0.05),and the increase of ROS in Cd-Se group was significantly alleviated(P<0.05);Compared with control group,MDA content in testis tissue of Cd group was significantly increased,while the contents of other oxidative stress indexes(CAT,SOD,GSH,GSH-PX)were significantly decreased(P<0.05).The content of MDA in testicular tissue of Cd-Se group was significantly decreased compared with that of Cd group,while the contents of other oxidative stress indexes(CAT,SOD,GSH,GSH-PX)were significantly increased(P<0.05)5.Quantitative PCR and Western-blot detection of endoplasmic reticulum stress genes(GRP78,PERK,IRE1,ATF6,CHOP,JNK)in testicular tissue showed that the expression levels of endoplasmic reticulum genes in Cd group were significantly up-regulated(P<0.05).The expression level of endoplasmic reticulum stress gene in Cd-Se co-treated group was significantly decreased compared with that in Cd group(P<0.05).6.Quantitative PCR and Western-blot detection of programmed necrosis genes(TNF-α,TNFR1,RIP1,RIP3,MLKL,Capase-8,PARP1)in testicular tissue showed that the expression level of Capase-8 in Cd group was significantly down-regulated compared with control group(P<0.05).The expression levels of other genes(TNF-α,TNFR1,RIP1,RIP3,MLKL,PARP1)were significantly up-regulated(P<0.05).The expression level of Capase-8 in Cd-Se co-treatment group was significantly increased compared with that in Cd group(P<0.05),while the expression levels of other genes(TNF-α,TNFR1,RIP1,RIP3,MLKL,PARP1)were significantly down-regulated compared with Cd group(P<0.05).These results indicate that Se alleviates Cd-induced toxic damage to chicken testis,including behavioral and mental abnormalities,decreased body weight and testicular weight,curving seminiferous tubule swelling and thinning of spermatogenic epithelium,decreased testosterone levels,occurrence of oxidative stress and endoplasmic reticulum stress,and activation of programmed necrosis. |
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