Suppression of cytochrome c release and apoptosis in testes with heat stress by minocycline.
Spermatogenic cells are susceptible to heat stress and undergo apoptosis. Although a variety of factors appear to be involved in the apoptotic process, the nature of the intracellular signaling pathway is ambiguous. To clarify the process, we chose a simple model in which testes of mice were exposed to mild heating by immersion in hot water at 42 degrees C for 15 min. In situ DNA fragmentation was detected by a TUNEL method. The release of cytochrome c into the cytoplasm was observed by Western blotting both in heat-treated testis and in isolated spermatogenic cells that had been incubated at 42 degrees C for 1h, but not in Sertoli cells. Minocycline, a semisynthetic tetracycline, is known to reach the brain by permeating the blood-brain barrier and suppresses apoptosis in neuronal cells. Since the testis also has a similar barrier, minocycline was examined as a possible agent to inhibit heat stress-induced apoptosis. The results indicate that minocycline suppressed the release of cytochrome c from mitochondria both in vivo and in vitro and significantly decreased the number of TUNEL-positive cells. These findings suggest that heat stress of testes triggers the release of cytochrome c from mitochondria in spermatogenic cells, leading to the activation of an apoptotic pathway.
Matsuki
Shingo
S
Department of Biochemistry, Yamagata University School of Medicine, 2-2-2 Iidanishi, Yamagata 990-9585, Japan.
Iuchi
Yoshihito
Y
Ikeda
Yoshitaka
Y
Sasagawa
Isoji
I
Tomita
Yoshihiko
Y
Fujii
Junichi
J
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D045304:Cytochromes c / Q000378:metabolism*; D018882:Heat Stress Disorders / Q000201:enzymology* / Q000503:physiopathology; D018869:Heat-Shock Response / Q000187:drug effects*; D008297:Male; D051379:Mice; D008911:Minocycline / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012708:Sertoli Cells / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D013090:Spermatocytes / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D013737:Testis / Q000187:drug effects* / Q000201:enzymology* / Q000473:pathology
D045304:Cytochromes c; D008911:Minocycline