磨牙缺失对幼年大鼠海马神经元凋亡及Caspase-3蛋白表达的影响

Effect of molar-missing on hippocampus nerve cell apoptosis and Caspase-3 protein expression in young rats

目的观察磨牙缺失后对幼年大鼠海马CA1区神经元细胞凋亡及海马神经元中Caspase-3的表达的影响,以探讨磨牙缺失幼年大鼠海马神经细胞凋亡可能的机制。方法雄性SD大鼠,4~5周龄60只,按完全随机设计平均分成对照组、实验组(磨牙缺失组)(n=30),再依据造模后断头取脑时间将30只大鼠随机分成4周组、8周组、20周组,采用HE染色及免疫组织化学法检测Caspase-3蛋白的表达情况,及末端标记法(TUNEL)法观察大鼠脑内神经细胞凋亡的变化。结果 1对照组海马CA1区细胞形态结构正常,无明显病理性改变。实验组细胞出现肿胀、空泡,结构排列紊乱,神经元细胞明显减少。2在4周、8周、20周,对照组Caspase-3无统计学差异(P=0.301),实验组海马CA1区Caspase-3阳性细胞数增加,差异有统计学意义(P=0.000),任意两组相比Caspase-3表达差异均有统计学意义,P<0.001;3实验组在不同时间段TUNEL阳性细胞数有统计学差异(P=0.000),对照组无统计学差异(P=0.276);两组相比表达差异有统计学意义(P<0.001)。结论长时期咀嚼刺激减少会导致大鼠海马区细胞凋亡增多,同时可上调Caspase-3蛋白的表达,提示长时期磨牙缺失诱导加快致发育期的大鼠海马组织细胞发生凋亡。

Objective To observe the influence of molar-missing on apoptosis of hippocampus CA1 neurons and expression of Caspase-3 in hippocampus neurons of young rats, and to investigate the possible mechanism of juvenile molar-missing on hippocampus neural cell apoptosis in young rats. Methods 60 male SD rats （ at the age of 4 - 5 weeks） were randomly divided into control group and experimental group, 30 in each group. And then 30 rats were randomly divided into three groups（4-week group, 8-week group and 20 -week group） based on when the modeling ended down to observe the expression of Caspase-3 protein by using HE staining and immunohistochemistry, and to observe the dynamic changes of nerve cell apoptosis in rat hippocampus by using TUNEL method. Results 1. The morphology and structure of hippocampus CAI cells were normal in the control group, and there were no significant pathological changes. The cells in the experimental group were swollen, vacuoles appeared, the structural arrangement became disordered, and the neuron cells were significantly reduced. 2. With time variation（4,8,20 weeks）, positive cells in hippocampus CA1 region of experimental group by the number increased, and the difference was statistically significant （P=0.000）, while in the control group there was no statistical difference （P= 0.301 ） in Caspase-3 expression. The differences were statistically significant in Caspase-3 expression between any two groups （P〈0.001）. 3.The TUNEL positive cells in experimental group had a statistically significant difference （P = 0.000）. The TUNEL positive cells in control group had no significant difference （P= 0.276）. There was a statistically significant difference in the number of TUNEL positive cells between any two groups （ P〈0.001 ）. Conclusion Longrun chewing stimulation decrease may increase apoptosis in hippocamptts of rats and may increase the expression of Caspase-3 protein at the same time. The results suggest that the long-term molar deletion in rat hippocampus induces the development of apoptosis of hippocampus tissue cells.