The mitochondrial-dependent pathway is chronically affected in testicular germ cell death in adult rats exposed in utero to anti-androgens.
In utero exposure to exogenous anti-androgenic compounds induces a wide range of abnormalities of the reproductive system, including hypospermatogenesis, cryptorchidism and hypospadias. By using rats exposed in utero to the anti-androgenic compound flutamide (0.4, 2 or 10 mg/kg per day), it has been shown that hypospermatogenesis in adult testes could be related to (i) a long-term apoptosis in germ cells but not in somatic Leydig and Sertoli cells as evidenced by the TUNEL approach and (ii) alterations in the mRNA and protein expression of pro- (Bax, Bak, Bid) and anti-apoptotic (Bcl-2, Bcl-w) members of the Bcl-2 family. Indeed, the number of apoptotic germ cells increased with the dose of flutamide administered and the apoptotic germ cells were mainly detected at androgen-dependent stages VII-VIII. Moreover, for the Bcl-2-related proteins that were expressed mainly in the germ cells, a decrease in the levels of anti-apoptotic peptides Bcl-w (60%, P=0.003) and Bcl-2 (90%, P=0.0001) was observed at 2 mg/kg per day flutamide and an increase in levels of the pro-apoptotic Bax (2.3-fold, P=0.0004) was detected at 10 mg/kg per day. In contrast, the levels of pro-apoptotic peptide Bak that was mainly expressed in somatic cells decreased (70%, P=0.0008) at 10 mg/kg per day. Such alterations in Bcl-2-related peptides occurred mainly at the protein level except for Bcl-2 (72%, P=0.0001) and Bak (43%, P=00002) transcripts. Together, these results showed that the apoptosis observed in adult germ cells from rats exposed in utero to flutamide may result from a long-term alteration in the balance between pro- and anti-apoptotic Bcl-2-related molecules in favour of pro-apoptotic proteins. These data further supported the concept of an androgen-dependent fetal programming that is in relation with an alteration of the expression of Bcl-2-related genes/proteins promoting apoptosis in testicular germ cells of adult rats with fetal androgen disruption.
Bozec
A
A
Institut National de la Santé et de la Recherche Médicale (INSERM U 407), Faculté de Médecine Lyon-Sud, BP 12, 69921 Oullins, France.
Chuzel
F
F
Chater
S
S
Paulin
C
C
Bars
R
R
Benahmed
M
M
Mauduit
C
C
D000726:Androgen Antagonists / Q000378:metabolism / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D047108:Embryonic Development / Q000187:drug effects*; D005260:Female; D005485:Flutamide / Q000378:metabolism / Q000633:toxicity*; D015870:Gene Expression / Q000187:drug effects; D019254:Genes, bcl-2; D007150:Immunohistochemistry / Q000379:methods; D020287:In Situ Nick-End Labeling; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013091:Spermatogenesis / Q000187:drug effects; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects*
D000726:Androgen Antagonists; D005485:Flutamide