[Clinical study of the correlation among the levels of human corticotropin-releasing hormone, c-Fos and connexin-43 at onset of labor].
OBJECTIVE
To investigate the variation of corticotropin-releasing hormone (CRH) in plasma, the mRNA and protein expression of c-Fos and gap junction gene connexin-43 (Cx43) in the myometrium of term pregnancy women, and to study the correlations among CRH, Cx43 and c-Fos at onset of labor.


METHODS
30 cases in labor (L group), 30 cases not in labor (NL group) but in term pregnancy, and 30 cases of non-pregnant (NP group) women undergoing hysterectomy due to cervical intraepithelial neoplasia were recruited into this clinical study. Radioimmunoassay was employed to measure the concentration of CRH in plasma; in situ hybridization assay and streptravidin-biotin peroxidase (SP) immunohistochemical techniques were respectively used to detect the expression levels of c-Fos mRNA, Cx43 mRNA and the corresponding proteins.


RESULTS
(1) The concentration of CRH in L group (81.8 +/- 11.9) pmol/L was significantly higher than that in NL group (34.5 +/- 18.6) pmol/L (P < 0.05), which was significantly higher than that in NP group (1.3 +/- 0.7) pmol/L (P < 0.05). (2) Most of the positive staining of c-Fos mRNA and protein in myometrium were located in cell nuclei and a few were in cytoplasm; and the expression level of c-Fos mRNA and protein were 5.4 +/- 1.7 and 5.4 +/- 1.5 in L group, 4.1 +/- 0.9 and 3.9 +/- 0.9 in NL group, 1.0 +/- 0.4 and 1.2 +/- 0.4 in NP group, respectively. There was a significant difference among different groups (P < 0.05). (3) The positive staining of Cx43 mRNA and protein in myometrium was located in the cytoplasm; and the expression level of Cx43 mRNA and protein was 5.5 +/- 1.4 and 5.6 +/- 1.3 in L group, 4.1 +/- 0.6 and 4.1 +/- 0.5 in NL group, 1.5 +/- 0.6 and 1.1 +/- 0.6 in NP group, respectively. There was a significant difference among different groups (P < 0.05). (4) In each group, there was a positive correlation between plasma CRH concentration and the expression of c-Fos mRNA and protein in myometrium (r(1) = 0.61, r(2) = 0.50; P < 0.05); between plasma CRH concentration and the expression of Cx43 mRNA and protein in myometrium (r(3) = 0.52, r(4) = 0.68; P < 0.05). A positive correlation was also found with respect to the expression of mRNA and protein between c-Fos and Cx43 (r(5) = 0.51, r(6) = 0.60; P < 0.05).


CONCLUSIONS
Plasma CRH, the expression of c-Fos and Cx43 in myometrium of women in term pregnancy are correlated with the onset of labor. There is a positive correlation among plasma CRH level, c-Fos and Cx43 expression in myometrium.
Wu
Xiang
X
Department of Gynecology and Obstetrics, Second Xiangya Hospital, Central South University, Changsha 410011, China.
Ding
Yi-ling
YL
Yu
Ling
L
D000328:Adult; D018031:Connexin 43 / Q000096:biosynthesis* / Q000235:genetics; D003346:Corticotropin-Releasing Hormone / Q000097:blood*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007150:Immunohistochemistry; D007745:Labor Onset / Q000502:physiology*; D009215:Myometrium / Q000166:cytology / Q000378:metabolism*; D011247:Pregnancy; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011863:Radioimmunoassay
D018031:Connexin 43; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D003346:Corticotropin-Releasing Hormone