No abstract

| The ejaculate composition is extremely complicated and variable among livestock species. The seminal proteins and enzymes are vital for ejaculate metabolism, spermatozoa performance, survival, and transport within the feminine reproductive tract. Proteases and proteinase inhibitors are secreted by the accessory sex glands of the male reproductive tract and find mixed with the spermatozoa throughout ejaculation. But an entire understanding of those enzymes and their performance in numerous class species is not obtainable. The performance of the assorted proteinases and protease inhibitors of ejaculate stay a mystery, and only a few studies are conducted concerning the characterization of those enzymes. Throughout this review, we tend to target the current understanding of the key proteases and their inhibitors of ejaculate from various mammalian species.

Large number of proteases have been identified in different parts of the male reproductive tract which play a crucial role during testicular development, epididymal sperm maturation, and sperm-oocyte fusion. The ADAMTS10 is a member of metalloproteinase family, the expression of which is important in sperm-oocyte interaction at the time of fertilization in mouse. In this species, the expression of ADAMTS10 has been demonstrated in testis, and on surface of spermatozoa from caput, corpus and cauda epididymis. Whether ADAMTS10 plays any role in male fertility of any of the domestic ruminant species including buffaloes is not known so far. Thus, a study was conducted to detect the expression of ADAMTS10 in testis, different parts of the epididymis and ejaculated spermatozoa of water buffalo (Bubalus bubalis) using real-time PCR, Western blot, and indirect immunofluorescence techniques. The highest expression of ADAMTS10 transcript was observed in corpus epididymis, followed by cauda, caput and testis. The Western blot detection of ADAMTS10 using the heterologous antibody has demonstrated 31-, 44-, 50-, 65 kDa immune-reactive protein bands from testis and 82 kDa protein from both testes and corpus epididymis and a major 36 kDa protein from ejaculated spermatozoa. The indirect immunofluorescence study has demonstrated high fluorescence signal in post-acrosome and the middle piece region of the ejaculated spermatozoa. Thus the differential expression pattern of ADAMTS10 in different parts of male reproductive tract of buffalo indicates their role in sperm maturation process. However, specific role of ADAMTS10 in buffalo male reproduction can only be ascertained after further studies.

No abstract

The motility and fertility of mammalian spermatozoa are compromised when they are cryopreserved. Sperm mitochondrial proteins play a vital role in conferring motility. However, the effects of cryopreservation on mitochondria-specific proteins remain primarily unexplored in domestic animals, including buffaloes, so the present study aimed to evaluate this issue. Mitochondria were isolated from both non-cryopreserved and cryopreserved buffalo spermatozoa by sonication followed by sucrose density gradient ultracentrifugation. The purity of the mitochondrial preparation was assessed by cytochrome oxidase assay and electron microscopy. Mitochondria separated from cryopreserved buffalo spermatozoa were associated with significantly lower (P ≤ 0.05) cytochrome oxidase activity as compared with non-cryopreserved spermatozoa. The intensities of two low-molecular-mass mitochondrial proteins (30.1 kDa and 26.1 kDa) were significantly reduced as compared with the non-cryopreserved group. In addition, in cryopreserved buffalo sperm mitochondria, the intensities of three tyrosine phosphorylated proteins (126.6, 106.7 and 26 kDa) increased significantly compared with the non-cryopreserved group. Of these, tyrosine phosphorylation of the 26-kDa mitochondrial protein of cryopreserved sperm was very intense and unique because it could not be detected in the mitochondria of non-cryopreserved sperm. Thus, the study confirmed that both cytochrome oxidase activity and the proteins of buffalo sperm mitochondria undergo significant cryogenic changes in terms of quantity and quality after a cycle of freezing and thawing and this may be one of the important causes of reduced post-thaw motility and fertility of cryopreserved buffalo spermatozoa.