Histomorphometric analysis and immunolocalization of RANKL and OPG during the alveolar healing process in female ovariectomized rats treated with oestrogen or raloxifene.
OBJECTIVE
To investigate the effects of bone-resorption inhibitors (oestrogen and raloxifene) on the RANKL/OPG balance during the chronology of the alveolar healing process in ovariectomized (OVX) rats by means of immunocolocalization and histomorphometric analysis.


METHODS
One hundred sixty female Wistar rats at 70 days of age were either OVX or sham-operated and divided into four groups: sham, OVX/Oil, OVX with E(2) replacement (17beta-estradiol, 400 microg/month), OVX with RLX treatment (1mg/kg bw/day). The 60-day treatment started 8 days after ovariectomy. The incisors were extracted to allow analysis of 7, 14, 21, 28 and 42 days of wound healing. After obtaining the histological samples, slides were stained with hematoxylin and eosin or subjected to immunocolocalization reaction for RANKL and OPG. Results were quantitatively evaluated.


RESULTS
Histomorphometric analysis showed that the sham group presented the highest and OVX/Oil group the lowest mean bone formation value in the post-extraction period. The immunocolocalization analysis showed a larger increase in bone turnover at 7 postoperative days in OVX/Oil and sham groups and decreasing bone turnover in the other periods. The OVX/Oil group showed a large decrease in bone turnover at 14 postoperative days, a period demonstrated by mild cellular activity. OVX/E(2) and sham groups showed a decreased bone turnover at 28 postoperative days while OVX/RLX group showed a decreased bone turnover at 21 postoperative days. On the 42nd postoperative day, sham and OVX/RLX groups showed an established alveolar bone healing process.


CONCLUSIONS
Ovariectomy delays the alveolar healing process and interferes with bone turnover through the balance between RANKL and OPG. Oestrogen replacement or raloxifene treatment did not totally recover the oestrogen-deficient state. However raloxifene treatment showed more satisfactory results than oestrogen replacement.
Luvizuto
Eloá Rodrigues
ER
UNESP - Univ Estadual Paulista, Araçatuba Dental School, Department of Surgery and General Clinical, Brazil. eloaluvizuto@hotmail.com
Queiroz
Thallita Pereira
TP
Dias
Sheila Mônica Damásio
SM
Okamoto
Tetuo
T
Dornelles
Rita Cássia Menegati
RC
Garcia
Idelmo Rangel
IR
Okamoto
Roberta
R
D000539:Alveolar Process / Q000187:drug effects*; D000704:Analysis of Variance; D000818:Animals; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D007180:Incisor; D053244:Osteoprotegerin / Q000378:metabolism*; D010052:Ovariectomy; D053245:RANK Ligand / Q000378:metabolism*; D020849:Raloxifene Hydrochloride / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014081:Tooth Extraction; D014945:Wound Healing / Q000187:drug effects
D004967:Estrogens; D053244:Osteoprotegerin; D053245:RANK Ligand; D020849:Raloxifene Hydrochloride