Mmp-9 Expression In The Castration Periodontitis In Rat Periodontal Tissue

Objective: In this research, the relationship between blood estrogen level and periodontitis in rats was studied .Methods Twenty-four female Wister rats were randomly divided into three groups: control group, sham operation group and ovariectomized group. Rat chronic periodontitis model was established by ligating the rat's second molar with a steel wire in the sham operation group and ovariectomized group. Serum estrogen level of the rats was detected respectively. Dental X-ray observation, Histological examination and Immunohistochemistry were employed for the characterization of rat's chronic periodontitis.Results: Compared with both control group and sham operation group, a significant decrease in scrum estrogen level was observed in ovariectomized group (P<0.01). X-ray observation indicates severe alveolar bone absorption happened to the ovariectomized group. Massive neutrophils infiltration in unctional epithelium was also confirmed by Histological examination. However, the above-mentioned chronic periodontitis symptom was not so significant in the rats of sham operation group. While MMP-9, as examined by Immunohistochemistry, was revealed as strong positive in the second molar's gingival tissues and periodontitis ligament of the rats in ovariectomized group. Expression of MMP-9 was much lower in sham operation group and even fewer in control group.Conclusions: Lower estrogen level play an improving role in the development of periodontitis.MMP-9 may participate in the periodontal tissue destruction.