[Roles of proto-oncogene c-erbB2 during the initiation growth of rat primordial follicles].
OBJECTIVE
To study the expression and possible roles of proto-oncogene c-erbB2 during the initiation growth of primordial follicles.


METHODS
Ovaries were collected from 2-day-old SD rats and cultured in the Waymouth culture system. In-situ hybridization, RT-PCR and immunohistochemistry were performed to assess the expressions of c-erbB2 mRNA and protein during the initiation growth of primordial follicles and after the effect of EGF. Western blot was used to observe the PCNA, p-ERK1/2 contents and correlation analysis was used to study the correlation relationship between contents of p-ERK1/2 and expressions of c-erbB2 mRNA at the same time of the primordial follicles growth.


RESULTS
PCNA protein levels appeared to be more intense during the initiation growth of primordial follicles, EGF could promote the proliferation and differentiation of the primordial follicles. c-erbB2 mRNA existed in the oocytes endochylema and ErbB2 existed in the oocytes membrane, the expressions of c-erbB2 mRNA and ErbB2 appeared to be more intense when primordial follicles were cultured for 8 d than cultured for 0 d in the Waymouth culture system and were further increased with 50 ng/ml EGF for 4 d and 8 d. The same results were observed by RT-PCR, too. p-ERK1/2 protein levels were consistent with the changes of c-erbB2 mRNA and protein. Furthermore, Spearman rank correlation analysis showed there was a significant positive correlation relationship between the changes of p-ERK1/2 and the changes of c-erbB2 mRNA during the primordial follicles growth and after the effect of EGF (rs = 0.900, P < 0.05).


CONCLUSIONS
It was suggested that proto-oncogene c-erbB2 may be play an important role during the initiation growth of primordial follicles with EGF, and it is indirectly suggested that c-erbB2 promotes the development of the primordial follicles via ERK-MAPK signal transduction.
Huang
Jian
J
Department of Physiology Reproduction, Medical College of Nanchang University, USA.
Zheng
Li-ping
LP
Li
Fang
F
Wu
Lei
L
Xu
Liang-quan
LQ
Xu
Ai-xia
AX
Pan
Xiao-ling
XL
Zheng
Yue-hui
YH
D000818:Animals; D000831:Animals, Newborn; D004815:Epidermal Growth Factor / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D009924:Organ Culture Techniques; D006080:Ovarian Follicle / Q000254:growth & development*; D010053:Ovary / Q000254:growth & development*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
D004815:Epidermal Growth Factor; D048049:Extracellular Signal-Regulated MAP Kinases; D012333:RNA, Messenger; D018719:Erb-b2 Receptor Tyrosine Kinases