[Effects of gonadotroph-releasing hormone analogues on follicle apoptosis in rats with chemotherapy-induced ovarian damage].
OBJECTIVE
To study the effects of gonadotroph-releasing hormone (GnRH) agonist (GnRH-a) and GnRH antagonist (GnRH-ant) on cyclophosphamide (CTX)-induced follicle apoptosis in female rats.


METHODS
Thirty-six female Sprague- Dawley rats were randomized into 6 groups, namely normal saline (NS), CTX, GnRH-a+NS, GnRH-a+CTX, GnRH-ant+NS, and GnRH-ant+CTX groups. The rats were sacrificed between the first and second week after the treatments., and the follicle apoptosis was investigated using TUNEL assay and transmission electron microscopy.


RESULTS
The apoptosis rate of the granulose cells in the follicles in late development was significantly higher than that in early follicles, and the apoptosis rate of the oocytes and granulose cells in rats with CTX treatment was significantly higher than that in rats without CTX treatment (P<0.05). The apoptosis rate of the granulose cells in GnRH-a groups (ranging from 33.40 - or + 4.59 to 73.25 - or + 5.35) was significantly higher than that in GnRH-ant groups (27.46 - or + 4.52 to 49.38 - or + 5.02, P<0.05), but there was no significant difference in the oocytes of early follicles between GnRH-a groups (23.48 - or + 4.25 to 36.15 - or + 4.23) and GnRH-ant groups (21.47 - or + 3.81 to 34.04 - or + 5.54, P>0.05). Electron microscopy revealed characteristic apoptotic changes of the oocytes in early follicles and granulose cells in early and late follicles. The apoptotic changes were especially typical in the granulose cells showing the formation of the apoptotic bodies, and the oocytes only showed chromatin condensation and aggregation.


CONCLUSIONS
In the rat mode, GnRH-a promotes while GnRH-ant suppressed follicle apoptosis induced by CTX. GnRH analogues regulates mainly granulose cell apoptosis, but have little effect on oocyte apoptosis.
Peng
Ping
P
Department of Obstetrics and Gynecology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China. pengping1967@yahoo.com.cn
Mo
Ya-qin
YQ
Yang
Chuan-hong
CH
Zhang
Wei
W
Zhang
Yan-ling
YL
Liu
Jia
J
Ye
Chang-lan
CL
Yang
Dong-zi
DZ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D003520:Cyclophosphamide / Q000633:toxicity*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors; D006107:Granulosa Cells / Q000473:pathology; D009865:Oocytes / Q000473:pathology; D006080:Ovarian Follicle / Q000473:pathology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D007987:Gonadotropin-Releasing Hormone; D003520:Cyclophosphamide