The role of transient receptor potential vanilloid receptor-1 (TRPV1) has been primarily investigated in pain sensory neurons. Relatively, little research has been performed in testicular cells. TRPV1 is abundantly expressed in Leydig cells of young adult mice. This study was conducted to determine the role of the TRPV1 channel in Leydig cells. TRPV1 modulators and testosterone were treated to the mouse Leydig cell line TM3 cells for 24 h. Capsaicin, a TRPV1 activator, dose-dependently induced cell death, whereas capsazepine, a TRPV1 inhibitor, inhibited capsaicin-induced cell death. Testosterone treatment reduced capsaicin-induced cell death. High concentrations of testosterone decreased TRPV1 mRNA and protein expression levels. However, TRPV1 modulators did not affect testosterone production. These results showed that capsaicin induced cell death of Leydig cells and that testosterone reduced capsaicininduced cell death. Our findings suggest that testosterone may regulate the survival of Leydig cells in young adult mice by decreasing the expression level of TRPV1.

Aquaporin channels (AQPs) are known to play an important role in the development of ovarian follicles through their function in water transport pathways. Compared to other AQPs, research on the role of AQP4 in female reproductive physiology, particularly in cattle, remains limited. In our previous study, gene chip microarray data showed a downregulation of AQP4 in bovine cystic follicles. This study was performed to validate the AQP4 expression level at the protein level in bovine follicles using immunohistochemistry, Western blotting, and immunoprecipitation assays. Immunostaining data showed that AQP4 was expressed in granulosa and theca cells of bovine ovarian follicles. The ovarian follicles were classified according to size as small (< 10 mm) or large (> 25 mm) in diameter. Consistent with earlier microarray data, semi-quantitative PCR data showed a decrease in AQP4 mRNA expression in large follicles. Western blot analysis showed a downregulation of the AQP4 protein in large follicles. In addition, AQP4 was immunoprecipitated and blotted with anti-AQP4 antibody in small and large follicles. Accordingly, AQP4 exhibited a low expression in large follicles. These results show that AQP4 is downregulated in bovine ovarian large follicles, suggesting that the downregulation of AQP4 expression may interfere with follicular water transport, leading to bovine follicular cysts.

Reproductive potential decreases with age. A decrease in male fertility is due to a combination of morphological and molecular alterations in the testes. Transient receptor potential vanilloid receptor-1 (TRPV1) is associated with aging and lifespan, and its activation causes apoptotic cell death in various cell types. However, the effect of TRPV1 on testicular apoptosis in aged mice has not yet been reported. TRPV1 knockout (KO) mice had a longer lifespan than that of wild-type (WT) mice. Lifespan was increased by 11.8% in male TRPV1 KO mice compared to that in WT mice. TRPV1 KO males lived approximately 100 days longer than WT males on average, and the maximum lifespan was markedly extended in TRPV1 KO mice compared with that in WT mice. The TRPV1 expression levels were highly increased in the testes of older mice. TRPV1 was expressed in the entire testes region of the old mice. In addition, old TRPV1 KO mice had lower testicular apoptosis than that of WT mice. Our results show that TRPV1 induces testicular apoptosis and suggest that TRPV1 may be associated with testicular aging.

Cryopreservation affects osmotic tolerance and intracellular ion concentration through changes in expression levels of water and ion channels. Control of these changes is important for cell survival after cryopreservation. Relatively little is known about changes in K+ channel expression compared to water channel expression. This study was performed to investigate changes in TASK-2 channel (KCNK5: potassium channel, subfamily K, member 5), a member of two-pore domain K+ channel family, in cryopreserved mouse ovaries. Cryopreservation increased TASK-2 mRNA expression in mouse ovaries. In addition, TASK-2 protein expression was upregulated in vitrified and slowly frozen ovaries. TASK-2 protein was expressed in all area of granulosa cells that surround the oocyte within the follicle, except nucleus. Viability of cells overexpressed with TASK-2 was higher than that of vector-transfected cells. Our results found that TASK-2 expression was increased by cryopreservation and overexpression of TASK-2 decreased cryopreservation-induced cell death. These results suggest that TASK-2 upregulation might reduce cryodamage.

Reproductive disorders in cows cause economic loss in livestock farms. Reproductive diseases, such as follicular cyst, luteal cyst, endometritis, pyometra, and repeat breeding cause infertility. Among these diseases, endometritis and pyometra are uterine infections that are leading causes of infertility. This study was performed to investigate the causative agents of uterine diseases using bacterial culture. Bacteria were obtained from the reproductive organs (vagina, uterine cervix, and uterine horn) of dairy cow diagnosed with endometritis or pyometra, and cultured on blood agar. The colonies obtained from cultivation for 24 hours were passaged. To identify the bacteria, the colonies grown in passaged culture Gram stained and applied to an automatic biochemical microbial identification system. Escherichia coli were commonly detected in vagina, uterine cervix, and uterine horn of dairy cows diagnosed to pyometra. The cows having endometritis showed not only Escherichia coli but also Pantoea spp. and Klebsiella spp. strains. Dairy cows that were infected with Escherichia coli in uterus caused mastitis or digestive disease. These results suggest that sanitary feeding and management beforehand are needed to prevent bacterial infections.

Alteration in ion channel or transporter expression levels affects cell volume which is produced by movement of water and ion across the plasma membrane. In particular, aquaporin (AQP) channels among ion channels play a crucial role in movement of water across the cell membrane. This study was performed to identify whether AQP expression is changed in bovine follicular cystic follicles using microarray, RT-PCR and Western blotting analyses. In microarray data, AQP4 expression was decreased, whereas AQP7 was increased in cystic follicles. Additional experiments were focused on the AQP7 expression increased in cystic follicles. The microarray data was confirmed by semi-quantitative polymerase chain reaction (PCR) and Western blot analysis. AQP7 mRNA and protein expressions were significantly increased in the cystic follicles (p<0.05). Application of estrogen (10 μg/ml) to bovine ovarian cells showed a trend of increase in AQP7 expression. From these results, we suggest that the increase in AQP7 expression in cystic follicles may play an important role in movement of water in bovine ovary. In addition, AQP7, a aquaglyceroporin permeating water and glycerol, could be a good target in development of methods for the cryopreservation of bovine ovary.