肾气丸和维生素E对D-半乳糖致衰老大鼠内耳线粒体DNA缺失率的影响

The Empirical Study on mtDNA4834 Deletion in Mimetic Aging Model Rat's Cochlear

目的研究肾气丸和维生素E对D-半乳糖致衰老大鼠内耳组织线粒体DNA(mtDNA)4834bp缺失率的影响。方法 40只3月龄大鼠分为D-半乳糖组、肾气丸组、维生素E组、对照组,每组10只。D-半乳糖组给予5%D-半乳糖500mg·kg-1·d-1颈部皮下注射,连续8周,肾气丸组给予同等剂量5%D-半乳糖颈部皮下注射6周后同时给予肾气丸混悬液5g·kg-1·d-1灌胃2周,维生素E组给予同等剂量5%D-半乳糖颈部皮下注射6周后同时给予维生素E250mg·kg-1·d-1喂服2周,对照组不注射D-半乳糖,在实验最后2周给予等量生理盐水灌胃。各组大鼠于实验前和给药结束后处死前行ABR检测,然后处死取内耳组织PCR扩增检测mtDNA4834片段缺失率。结果给药结束后,对照组大鼠ABR反应阈较D-半乳糖组、肾气丸组、维生素E组低(P<0.05),但三个实验组间差异无统计学意义(P>0.05);D-半乳糖组、肾气丸组、维生素E组及对照组内耳组织线粒体DNA 4834bp缺失突变率分别为88.8%、60.0%、50.0%及0%,前三组缺失率明显高于对照组,但肾气丸组、维生素E组缺失率明显低于D-半乳糖组(P<0.05)。结论肾气丸和维生素E均能降低D-半乳糖致老化大鼠内耳组织mtDNA 4834bp的缺失率。

Objective To study the effect of Shenqiwan and vitamin E on mtDNA4834 deletion in a mimetic aging rat model. Methods Forty rats three months old, were randomly divided into four groups： group A, which was treated with hypodermic 5 % D-galactose for 8 weeks, and group B （shenqiwan group, n= 10） which was treated daily with Shenqiwan for 2 weeks after hypodermic 5 ~ D-galactose for 6 weeks, group C （vitamin E group, n = 10） which were treated daily with Vitamin E for 2 weeks after hypodermic 5 % D-galactose for 6 weeks, group D were given saline only. Auditory brainstem response （ABR） was used to detect the hearing thresh- old of rats before and after the treatment. The inner ear tissue was harvested and mitochondrial DNA was amplified to identify the 4834 bp deletion mutation by nested primer polymerase chain reaction （nested PCR） technique. Re- suits The threshold of ABR in the group A, B and C were significant higher than that in group D. However the difference in shift of ABR threshold between group A, B, C and group D was not significant. The mtDNA4834 de- letion rate in three modeled groups （group A, B, C） was significant high than that of in group D. There was statis- tically significant difference between the treated group （group B, C） and the model group （group A） on mtDNA4834 deletion in cochlea, but the difference between the treated groups on mtDNA4834 deletion in cochlea was not statistically significant. Oonclusion Shenqiwan and vitamin E can reduce the aging induced mtDNA4834 deletion in aging rats inner ear.