Differential effects of 17β-estradiol on knee and temporomandibular joints in ovariectomized rats

This study aimed to investigate the therapeutic effects of different concentrations of 17β-estradiol (E2) on knee joints (KJ) and temporomandibular joints (TMJ) in ovariectomized rats, with a focus on bony changes and inflammation. Bilateral ovariectomy was performed to induce estrogen deficiency, and various concentrations of E2 were administered (0, 10, 50, or 100 μg/100 g body weight (BW)) to explore joint responses. Microcomputed tomography and histological and immunohistochemical staining techniques were used to evaluate bony changes and inflammatory markers. We observed significant differences in joint responses between the two joints, with 10 μg/100 g BW of E2 showing promising results in promoting bone recovery in the TMJ with minimal harmful effects on KJ. However, the high E2 concentration of 100 μg led to adverse effects, including bone sclerosis and increased inflammation in both joints. This study suggested that a low dose (10 μg /100 g BW) of E2 may have a therapeutic effect on osteoporotic changes in the TMJ following estrogen deficiency, with minimal harmful effects such as inflammation and side effects on other joints.