Left: Normal spermatogenesis in the scrotum (34 ° C )Right: Impaired spermatogenesis in the abdominal area (38 ° C).
Credit: NIBB Testicles of most mammals are cooled in the scrotum, and elevated testicular temperature levels result in spermatogenesis failure and male infertility. A team of scientists led by Shosei Yoshida at the National Institute for Basic Biology in Japan detailed this procedure using organ cultures and exposed that spermatogenesis suffers at numerous actions in a fragile temperature-dependent manner.
Testicles of most mammals are cooled in the scrotum, and elevated testicular temperatures lead to spermatogenesis failure and male infertility. A team of scientists led by Shosei Yoshida at the National Institute for Basic Biology in Japan detailed this procedure using organ cultures and exposed that spermatogenesis is impaired at several actions in a delicate temperature-dependent way.
Spermatogenesis is the procedure by which haploid spermatozoa establish from bacterium cells in the seminiferous tubules of the testis.
Numerous studies have been conducted on the heat problems of spermatogenesis by raising the testis temperature using animal designs, for example, surgical relocation of the testis to the abdomen. To get rid of these constraints, the research group took benefit of the testis organ culture setting that supports complete spermatogenesis in incubators, which was established by Takehiko Ogawa and associates at Yokohama City University.
Blue bars indicate the bacterium cell types observed in testis explants cultured at the indicated temperatures. * No germ cells endured at 40 ° C. Credit: NIBB
Many studies have actually been performed on the heat problems of spermatogenesis by raising the testis temperature level utilizing animal designs, for example, surgical moving of the testis to the abdomen. Actual testicular temperature level might not be controlled in these experiments. Moreover, the impacts of extra-testicular elements such as the endocrine and nerve systems can not be left out.
To conquer these constraints, the research study group took benefit of the testis organ culture setting that supports total spermatogenesis in incubators, which was developed by Takehiko Ogawa and associates at Yokohama City University. Credit: NIBB
The group even more revealed that meiosis, through which homologous chromosomes segregate into haploid sperms, was significantly impacted at 37– 38 ° C. Specifically, the repair of DNA double-strand breaks and homologous chromosome pairing, which are requisites for proper chromosome partition, suffered. Damaged cells undergo cell death through a monitoring mechanism or a checkpoint. Kodai Hirano, the main factor to this research study, states, “It was surprising that important procedures, such as meiosis, can be quickly damaged at typical body core temperature levels. Through the combined functions of the scrotum and checkpoint, only sperm established at low temperature levels fertilizes eggs to generate the next generation. Secret questions for future studies consist of the molecular mechanism of heat sensitivity and the biological significance of low temperature levels in sperm production.” This research study has been released in Communications Biology.
Referral: “Temperature level of sensitivity of DNA double-strand break repair underpins heat-induced meiotic failure in mouse spermatogenesis” by Kodai Hirano, Yuta Nonami, Yoshiaki Nakamura, Toshiyuki Sato, Takuya Sato, Kei-ichiro Ishiguro, Takehiko Ogawa, Shosei Yoshida, 26 May 2022, Communications Biology.DOI: 10.1038/ s42003-022-03449-y.
In particular, although spermatogenesis is completed at 34 ° C/93 ° F( the scrotal temperature level), warming to 37– 38 ° C/98.6– 100 ° F( temperature levels in the abdomen) badly impacts meiosis– the procedure of segregating homologous chromosomes into haploid sperms– and the damaged cells go through cell death. Showing the utility of organ culture, this research study will improve the study of heat vulnerability in spermatogenesis.