Figure 1.

Administration of E2 causes targeted loss of collagen and glycosaminoglycan (GAG) in mouse temporomandibular joint (TMJ) but not knee meniscus fibrocartilage. Seven days following ovariectomy, osmotic pumps containing phosphate buffered saline (control; C), 17-β estradiol (E2; 3 µg/kg/d), or progesterone (P4; 0.15 mg/kg/d as hormone control) were implanted subcutaneously in 12-wk-old female mice. One week after the pumps were implanted, the mice were euthanized and the tissues retrieved and assayed for collagen and GAG. Collagen (A) and GAG (B) content in TMJ disc was significantly reduced by E2 but not by P4 infusion. E2 did not modulate any changes in collagen (C) and GAG (D) content in knee meniscus (KM) fibrocartilage. Results are shown as mean ± SD from 5 mice. **P < 0.01 vs. control or P4-treated mice.