[The effect of shifting of estrogen level on the expression of estrogen receptor and morphology of condyle in rat].
OBJECTIVE
To evaluate the possible role and mechanism of estrogen in the morphologic alteration process of mandibular condyle.


METHODS
Forty healthy non-pregnant female 6-week-old Sprague-Dawley rats were randomly divided into control group, contraceptive group (intragastric administration with contraceptive), contraceptive + normal saline (intragastric administration with contraceptive and normal saline) and contraceptive +estradiol group(intragastric administration with contraceptive and estradiol) equally. The serum levels of estradiol were detected respectively before the experiment, on the twelfth week and sixteenth week. The rats were sacrificed after the experiment and the expression of ERα, ERβ of condyle was detected and histologic observation of the condyle was performed. SPSS11.0 software package was used for statistical analysis.


RESULTS
The serum estradiol concentration of the other 3 groups were significantly lower than control group at 12 week (P<0.05)； the serum estradiol concentration of contraceptive + estradiol group was significantly higher than contraceptive + normal saline group on sixteenth week (P<0.05). H-E and immunohistochemistry showed that compared with control group, not only retrogression occurred in rat condylar cartilage but also the expression of ERα and ERβ of condylar cartilage was decreased(P<0.05) in contraceptive group; Compared with the contraceptive + normal saline group, the retrogression was repaired and ERαexpression was increased(P<0.05) while ERβ was not increased (P>0.05) in contraceptive + estradiol group.


CONCLUSIONS
The lowered serum estrogen would lead to retrogression in condylar cartilage. Estradiol valerate could be used to raise concentration of serum estrogen, increase the expression of ERα and slow down the process of condylar cartilage retrogression through ER pathway.
Department of Oral and Maxillofacial Surgery, the 3rd Affiliated Hospital of Anhui Medical University. Hefei 230061, Anhui Province, China. E-mail:772000831@qq.com.
Peng
P
Xu
Chuan-Jun
CJ
Chen
D000818:Animals; D002356:Cartilage; D004958:Estradiol / Q000031:analogs & derivatives; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D008335:Mandibular Condyle / Q000033:anatomy & histology* / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000378:metabolism*
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D011960:Receptors, Estrogen; D004958:Estradiol