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目的:探讨大鼠偏侧咀嚼过程中大鼠咬肌过氧化物酶增殖激活受体γ协同刺激因子-1α(PGC-1α)、葡萄糖转运蛋白4(GLUT4)及线粒体损伤程度的表达变化规律,进一步研究偏侧咀嚼致咬肌功能紊乱的机制。方法:取8w龄健康雄性Wistar大鼠咬肌,用实时荧光定量PCR(real-time,PCR)法检测咬肌中PGC-1αmRNA及GLUT4mRNA的相对表达量;电镜观察线粒体形态和数目的变化并计算线粒体损伤指数。结果:拔牙侧与非拔牙侧PGC-1αmRNA表达量第4w最高,第8w最低;除第6w周组外,拔牙侧PGC-1αmRNA表达量明显高于非拔牙侧及对照组(P<0.01)。拔牙侧与非拔牙侧线粒体损伤评分第8w最高,4w最低;除第8w组外,拔牙侧线粒体损伤评分明显低于非拔牙侧及对照组(P<0.01)。拔牙侧与非拔牙侧GLUT4 mRNA的表达量第4w时最高,第8w时最低;2w组与4w组拔牙侧GLUT4mRNA的相对表达量明显高于对照组(P<0.01)。GLUT4与PGC-1α呈正线性相关(r值为0.8650,P<0.01);PGC-1α与线粒体损伤指数无明显的相关性。结论:偏侧咀嚼可引起咬肌线粒体损伤;PGC-1α可通过调控GLUT4的表达而调节咀嚼肌细胞的能量代谢,是偏侧咀嚼致咬肌功能紊乱的发生机制之一。
OBJECTIVE: To study the changes of the expression of peroxisome proliferator-activated receptor γ co-stimulatory factor-1α (PGC-1α), glucose transporter 4 (GLUT4) and mitochondrial damage during mastication in rats, Further study of unilateral chewing induced masseter muscle dysfunction mechanism. Methods: The masseter muscle of 8-w-old healthy male Wistar rats was used to detect the relative expression of PGC-1α mRNA and GLUT4 mRNA in the masseter muscle by real-time PCR. The changes of mitochondrial morphology and number were observed by electron microscopy Mitochondrial damage index. Results: The expression of PGC-1α mRNA in tooth extraction side and non-extraction side was the highest at 4w and the lowest at 8th week. The PGC-1α mRNA expression in tooth extraction side was significantly higher than that in non-extraction side and control group except the 6th week group (P <0.01). The mitochondrial damage score of the tooth extraction side and non-extraction side was the highest at 8th week and the lowest at 4 weeks. The score of mitochondrial injury in the tooth extraction side was significantly lower than that in the non-extraction side and the control group except the 8th group (P <0.01). The expression of GLUT4 mRNA in the tooth extraction side and non-extraction side was the highest at 4w and the lowest at 8w. The relative expression of GLUT4mRNA in the tooth extraction side of 2w and 4w groups was significantly higher than that of the control group (P <0.01). There was a positive linear correlation between GLUT4 and PGC-1α (r = 0.8650, P <0.01). There was no significant correlation between PGC-1α and mitochondrial damage index. Conclusion: Masticatory chewing can cause mitochondrial damage in masseter muscle. PGC-1α can modulate the energy metabolism of masticatory muscle cells by regulating GLUT4 expression, which is one of the mechanisms of masseter muscle dysfunction.