Figure 1.

Estrogen deficiency leads to bone loss. A. The estrogen expression level significantly decreased in the PMOP group compared with the control group. B. Morphometric analysis showed that the tibia/fibula in the control group was normal. C. The tibia/fibula exhibited osteoporosis in the PMOP model group. D. Subchondral boned showed a healthy bone mass in the control group. E. Bone loss of subchondral bone in the PMOP model group was detected. All these results revealed that estrogen deficiency could induce osteoporosis, and the PMOP model was successfully established.