Apoptotic cells and related factors in ovariectomized rat osteoporosis model / 中华内科杂志

ABSTRACT

Objective　To investigate the status of apoptosis of osteoblast, osteoclast and the relative factors. Methods　Apoptotic cells were examined using in situ end labeling technique. Expressions of bcl-2, Fas and transforming growth factor(TGF)β1 were observed with immunohistochemical method. Results　Positive expression rate (40.5±5.2)% of apoptosis cells was significantly increased in the osteoblast, but the expression rate of apoptosis cells (8.4±1.2)% was significantly decreased in the osteoclast of the post-ovariectomy rats than in the sham-operated rats. The expression of Fas was decreased in osteoclast (20.0%) and increased in osteoblast (80.0%) of the post-ovariectomized rats. The expression of TGFβ1 was significantly decreased in the osteoclast (0) and the osteoblast (20.0%) of the post-ovariectomized rats. The above-mentioned targets in post-ovariectomized rats treated with nilestriol/levonorgestrel were close to those sham-operated rats (P＞0.05). Conclusions　 Bone loss in the post-ovariectomized rats is attributable to the lower level of estrogen so that the apoptosis cells were decreased in osteoclast but were increased in osteoblast. As a result, the process of bone absorption prevails over that of bone formation. Expression of TGFβ1 depends on stimulation of estrogen. TGFβ1 may stimulate apoptosis of osteoclast and restrain apoptosis of osteoblast. Fas can induce the apoptosis of osteoclast.