中文摘要：

目的：检测不同硬度食物喂养下，大鼠在离乳后不同发育阶段咬肌神经营养因子3（Neurotrophin-3，NT-3）及其受体酪氨酸蛋白激酶C（Tyrosine Kinase C，TrkC）的表达变化。方法：对出生后18d刚离乳的大鼠分别喂养固体、粉状鼠粮，于大鼠3w、4w、6w、9w龄时取表层咬肌，利用RT—PCR方法检测NT-3及其受体TrkC mRNA的表达变化情况。结果：在出生后3-9w内，粉、固体组大鼠咬肌NT-3mRNA表达均明显下降（P〈0．05），粉食组NT-3mRNA在6w时表达低于固体组（P〈0．05）；TrkC mRNA在3-9w内持续下降，但粉、固体组间没有差异（P〉0．05）。结论：粉食喂养能够降低离乳后大鼠咬肌NT-3mRNA的表达，但对TrkC mRNA影响不大。

英文摘要：

Objective： To investigate the effects of diet consistency on the expression ofneurotrophin-3（NT-3）, and it＇ s receptors tyrosine kinase C （TrkC） in the rat masseter muscle during different development periods. Methods： The rats soon after weaning （18days after birth） were fed with ordinary rat solid or powder diet, the superficial masseter muscle was dissected when rats were 3 weeks, 4weeks, 6weeks, 9weeks after birth. The expression of NT-3/TrkC mRNAs was tested with RT-PCR. Results： From 3 to 9 weeks after birth, the level ofNT-3/TrkC mRNAs in rats masseter muscle of both groups decreased （P〈0.05）. The expression ofNT-3 mRNA in powder group was lower than solids group at 6 weeks （P〈0.05）, however, no significant differences were observed between powder group and solid group in the expression of TrkC mRNA （P〉0.05）.Conclusion： Powder diet can lower the expression ofNT-3 mRNA in rats masseter muscle after weaning, but has no obvious impacts on the expression ofTrkC mRNA.