The Expression Of Melatonin Receptor In The Epididymis Of Sheep

Melatonin plays an important role in the reproductive system through binding of melatonin receptor MT1 and MT2.The epididymis is an important reproductive organ of male animals which is important to sperm maturation and storage.This study investigated the expression and distribution of melatonin receptor in epididymis of sheep at different ages,and to provide a basis for the further study that melatonin regulate the epididymal function.The results were as follows:(1)The expression profile of MT1 mRNA in the different part of epididymis of the different age sheep were detected by real-time fluorescence quantitative PCR.The results showed that in the lamb(2?3 months old),MT1 transcription level at the epididymis cauda was higher significantly than these of corpus and caput.The transcription level of MTl in the corpus and cauda were significantly higher than that in the caput in the young ram(6?8 months old);in the adult ram(2?3 years old).The transcription level of MT1 in the cauda was significantly higher than these in the corpus and caput.With the growth of ram,the transcription level of MT1 in the epididymis was decreased.The expression profile of MT2 in the different part of epididymis of the different age sheep were detected by real-time fluorescence quantitative PCR.The results showed that in the lamb,the expression profile of MT2 in the caput was the higher than that in the corpus and cauda.In the young ram,MT2 had the highest level of transcription at the epididymis caput compared to that of corpus and cauda.MT2 transcription at the epididymis cauda was higher significantly than that of corpus.In the adult,the transcription level of MT2 in the caput and cauda was significantly higher than that in the corpus.With the growth of ram,the transcription level of MT2 in the epididymis was increased.(2)The melatonin receptor protein was located in different parts of the sheep epididymis at different ages by Immunohistochemical analysis.The result showed that MT1 and MT2 were distributed in the epididymis of sheep at different ages and were mainly distributed in epididymis epithelium.MT1 and MT2 proteins were also detected in the epididymal lumen of young and adult sheep.In summary,MT1 and MT2 were regularly expressed in different parts of the sheep epididymis.In the different parts of the sheep epididymis at different ages,melatonin may combine with melatonin receptor MT1 or/and MT2 proteins to exert the it's role.