咬合恢复对大鼠三叉神经节PPTA mRNA及其相应蛋白表达的影响

目的:研究咬合恢复对大鼠三叉神经节P物质(substance P,SP)及编码SP的前速激肽原A(PPTA)mRNA表达的影响.方法:Wistar雄性大鼠48只,随机分为3个实验组及相应的正常对照组,每组8只.实验组动物间断磨除右上、下颌磨牙牙冠至龈下,2组分别于第3、9周停止磨牙,任其自行萌出,恢复咬合关系.双侧三叉神经节(trigeminal ganglia,TG)切片行SP免疫组织化学反应(SABC法)和原位杂交反应.光镜观察摄片,并用Image Pro Plus 5.1图像分析软件进行测定.采用SPSS10.0软件包对数据进行统计学分析.结果:单侧咀嚼实验组咀嚼侧和非咀嚼侧TG内,SP阳性神经元百分比与对照组比较显著降低(P<0.01,P<0.05),其非咀嚼侧显著低于咀嚼侧(P<0.05);而PPTA mRNA阳性神经元百分比显著增高(P<0.01,P<0.05),其非咀嚼侧显著高于咀嚼侧(P<0.01).早期恢复咬合实验组TG内SP和PFTA mRNA阳性神经元百分比与对照组比较无显著差别(P>0.05),其咀嚼侧与非咀嚼侧比较无显著差别(P>0.05).晚期恢复咬合实验组TG内,SP和PPTA mRNA表达情况与单侧咀嚼实验组一致.结论:早期恢复咬合关系TG内SP和PPTA mRNA表达可恢复正常,晚期恢复咬合关系其表达不能恢复正常,SP和PPTA mRNA参与了单侧咀嚼引起的颞下颌关节病的病理变化过程.

The level of PPTA mRNA and its proteins expression in trigeminal ganglia in rats with occlusal recovery

PURPOSE: To study the level of substance P(SP) and preprotachykinin A(PPTA) mRNA in trigeminal ganglia(TG)in rats with occlusal recoveryìand to discuss the mechanism of temporomandibular disorders. METHODS: 48 Wistar male rats were randomly divided into 3 experimental groups and 3 control groupsì8 rats in each group. The right maxillary and mandibular molars in the experimental groups were ground to the gingival level without occlusal contact. The occlusal contact was recovered by stoping grinding the molars gradually. The section of trigeminal ganglia were used for immunohistological and in situ hybridization study. Light microscope and microscoic photo analytic software were employed to detect the percentage of SP and PPTA mRNA positive neurons in the frozen section of TGs in 48 rats. SPSS10.0 software package were used for statistical analysis. RESULTS: The percentage of SP positive neurons in TG with unilateral chew experimental group decreased significantly compared to the control group (P<0.01,P<0.05).The decreased extent in the non-chewing side was much higher than that in the chewing side(P<0.05).The percentage of PPTA mRNA positive neurons was significantly higher in both of the chewing and non-chewing sides of the unilateral chew experimental group than that in the control group (P<0.05,P<0.01)ì and that non-chewing side was significantly higher than that in the chewing side(P<0.01).There was no significant difference in the percentage of SP and PPTA mRNA positive neurons between the early occlusal reconstruction the experimental group and the control group(P>0.05), and there was no significant difference of those between the non-chewing side and the chewing side(P>0.05). The results of later occlusal recovery in the experimental group was same to that of the unilateral chew experimental group. CONCLUSIONS: The expressions of SP and PPTA mRNA in TG can recover normal in the early occlusal recovery but can not in the later occlusal recovery. SP and PPTA mRNA might participate in the histopathologic mechanism of temporomandibular disorders. Supported by Research Fund from Science and Technology Bureau of Taian City (Grant No.2003-52).