Apoptosis and expression of apoptosis-related genes in the mouse testis following heat exposure.
OBJECTIVE
To investigate molecular mechanisms of germ cell apoptosis induced by heat exposure in mice.


METHODS
Controlled laboratory study.


METHODS
Departments of Urology and Biochemistry, Yamagata University School of Medicine, Yamagata, Japan.


METHODS
Forty-four male B6D2F1 mice.


METHODS
Heat exposure, 43 degrees C for 15 minutes.


METHODS
Testicular germ cell apoptosis (percentages of apoptotic tubules and apoptotic cells) was assessed by using DNA nick-end labeling, and expression of Bcl-2 family, Fas-FasL system, and p53 was evaluated by using Western analysis.


RESULTS
Bilateral testicular weights decreased significantly from 3 days after heat exposure. Percentages of apoptotic tubules and apoptotic germ cells increased significantly from 1 day after heat exposure. There were no significant changes in the levels of Bcl-xl, Bad, and Bax after heat exposure. However, Bcl-2 expression level decreased significantly 7 days after heat exposure. In contrast, the expression level of Fas and p53 increased significantly from 1 day to 3 days after heat exposure, respectively. Expression level of FasL elevated significantly at days 1 and 2 but declined from day 3.


CONCLUSIONS
Germ cell apoptosis induced by heat exposure is mainly mediated by the Fas-FasL system.
Miura
Michiharu
M
Department of Urology, Yamagata University School of Medicine, Yamagata, Japan.
Sasagawa
Isoji
I
Suzuki
Yasuhiro
Y
Nakada
Teruhiro
T
Fujii
Junichi
J
D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D002352:Carrier Proteins / Q000032:analysis; D053222:Fas Ligand Protein; D006358:Hot Temperature; D020287:In Situ Nick-End Labeling; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis; D051379:Mice; D011518:Proto-Oncogene Proteins / Q000032:analysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D013737:Testis / Q000737:chemistry* / Q000166:cytology*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; D019014:fas Receptor / Q000032:analysis
C494820:Bad protein, mouse; C494827:Bax protein, mouse; C494812:Bcl2l1 protein, mouse; D002352:Carrier Proteins; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; D019014:fas Receptor