Genome-wide identification of gene expression in the epididymis of infertile rat induced by alpha-chlorohydrin using oligonucleotide microarray

Objective To establish a rat model of sterility associated with epididymis and epididymal gene expression profiles relation to fertility by alpha-chlorohydrin.Methods Rats were treated with 10 mg·kg-1·d-1.alpha-chlorohydrin for 10 consecutive days.Sperm maturation and other fertility parameters were analyzed.The sperm motility and morphology were evaluated by computer-assisted sperm analysis(CASA);sperm survival rate was assessed by SYBR-14 and propidium iodide(PI)fluorescent staining;the weights of testes,epididymides,prostates and seminal vesicles were determined by electronic balance;histological examination of above tissues were evaluated by HE staining;and serumal dihydrotestosterone(DHT)and testosterone(T)of rats were detected by enzyme-labeled immunoassay.Each male rat was paired with 2 female rats in proestrus.Female rats were examined the next morning for the presence of sperm in vaginal smears and underwent a cesarean section on day 12 of gestation.Finally the reproductive indices were calculated as follows:copulation index(number of sperm positive females /number of pairings),pregnancy index(number of pregnancies /number of sperm positive females),and fertility index(number of pregnancies /number of pairings).After that we used Affymetrix Rat 230 2.0 oligo-microarray to identify epididymal special genes associated with fertility.Finally,we validated some of these genes by Real-Time quantitative polymerase chain reaction.Results The motility of spermatozoa from the cauda epididymidis of treated rats showed a significant decrease in percentage of motile,progressively motile sperm,and sperm survival rate.At the same time,the morphology of cauda epididymal spermatozoa was also adversely affected by the treatment.In addition,the serumal androgen levels of treated animals weren't changed compared with the control group.Accordingly,matings with treated males resulted in no successful pregnancy.Then,we classified general functions of the down or up regulated epididymal genes by chlorhydrin with the GeneSpring gene ontology(GO)analysis,which are involved in macromolecular metabolism and transport,primary metabolism process,cell metabolism,biological process regulation,immunology regulation,ion combination,hydratase and oxidoreductase activity.Among all the different expressed genes,we analyzed and screened the down-regulated genes associated with glucose,lipid,protein and other energy metabolism,which are considered as the major ACH action targets.Simultaneously,the up-regulated genes by chlorhydrin were detected and their characters of negative regulated sperm maturation and fertility analyzed,which are apoptosis and immune-related genes and not reported before.Conclusions We established male infertile rat model with ACH(10 mg·kg-1·d-1,po,10 days)through evaluating changes of sperm motility and morphology,mating index,fertility index and pregnancy index.Simultaneously,the ACH didn't affect the major androgen(T and DHT)metabolism and sexual ability,which is considered as the best way for male contraception.Then we determined the down-regulated epididymal genes relation to substance metabolism,which can affect the epididymal sperm maturation and presumed the major antifertility targets by ACH.Further more,we found and analyzed the epididymal up-regulated genes associated with apoptosis and immune functions,which maybe the new possible sites of action by ACH and other male antifertility agents.