咀嚼力降低对大鼠髁突软骨中Bax和Bcl-2 mRNA表达的影响

Effect of low masticatory force on the expression of Bax and Bcl-2 mRNA of the condylar caitilage in growing rats

目的:探讨咀嚼力降低对发育期大鼠下颌髁突软骨中凋亡相关蛋白Bax和Bcl-2 mRNA表达水平的影响。方法:40只18d雄性大鼠随机分为2组。一组喂以标准的硬食,另一组以粉末状软食喂养。于大鼠4周、5周、6周、7周龄时取其髁突软骨以RT-PCR方法检测其中Bax和Bcl-2mRNA的表达水平。结果:正常硬食组大鼠髁突软骨中Bax mRNA和Bcl-2 mRNA的表达均随时间延长而降低。软食对Bcl-2 mRNA表达的影响不大,但却使Bax mRNA表达上调。软食组Bax mRNA与Bcl-2 mRNA的比值在6周和7周时明显高于硬食组(p<0.05)。结论:咀嚼力降低使发育期大鼠髁突软骨Bax mRNA表达水平和Bax mRNA/Bcl-2 mRNA的比值上升,但对Bcl-2 mRNA影响不大。

Objective： To estimate the effect of low masticatory force on the expression of Bax and Bcl-2 mRNA of the condylar cartilage in growing rats. Method： Forty 18 days old rats were randomly divided into 2 groups. One group received the normal hard diet foe rats; the other group received the powder soft diet. The condylar cartilages were dissected when rats were 4 weeks,5 weeks,6 weeks,7 weeks after birth. The expression of bax and Bcl-2 mRNAs were tested by RT-PCR. Result： From 4 to 7 weeks after birth, the level of Bax and Bcl-2 mRNA in condylar cartilage in normal hard diet group decreased. The expression of Bax mRNA in soft diet was significantly higher than that in hard group at 7 weeks （p 〈0.05）, however, no significant difference was observed between soft group and hard group in the expression of Bcl-2 mRNA. The ratio between Bax and Bcl-2 mRNA in soft diet group was higher than that in hard diet group at 6 and 7 weeks. Conclusion： The low masticatory force increased expression of Bax mRNA and the ratio between Bax mRNA and Bcl-2 mRNA in soft diet group of condylar cartilage in growing rats, but has no obvious impacts on the expression of Bcl-2 mRNA.