Estrogen deficiency reduces the expression of estrogen receptor-beta in Wistar rats’ periodontal tissues

OBJECTIVE: To assess the effect of ovariectomy on the expression of estrogen receptor-beta (ER-beta) in periodontal ligament and alveolar bone.

METHODS: This animal study was conducted at King Fahad Research Center, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia from March to October 2012. Thirty 12-week-old female Wistar rats were divided into 2 groups (15 each): ovariectomized (OVX) and sham-operated. Levels of estrogen and progesterone in the sera were measured using the enzyme linked immunosorbent assay (ELISA). To detect the expression of ER-beta, immunostaining was performed on the tibia, alveolar bone, and periodontal ligament specimens followed by quantitative histomorphometric analysis.

RESULTS: Estrogen (p=0.001) and progesterone (p=0.007) levels were significantly decreased in the OVX rats compared to their controls. Histologically, the thickness and area percentage of the tibia and alveolar bone trabeculae were significantly reduced in OVX rats compared to the controls (p=0.001). The periodontal ligament fibers in the control group exhibited well-organized and appropriately oriented fibers, while in the OVX group they appeared disrupted with loss of orientation. The ER-beta expression in the OVX rats was significantly decreased in the periodontal tissues (p=0.005) and tibia (p=0.008).

CONCLUSION: Estrogen deficiency resulted in a significant decrease in the expression of ER-beta in both tibia and periodontal tissues.