The effect of melatonin and vitamin C treatment on the experimentally induced tympanosclerosis: study in rats

Abstract Introduction: The ethiopathogenesis of tympanosclerosis has not been completely under- stood yet. Recent studies have shown that free oxygen radicals are important in the formation of tympanosclerosis. Melatonin and Vitamin C are known to be a powerful antioxidant, interacts directly with Reactive Oxygen Species and controls free radical-mediated tissue damage. Objective: To demonstrate the possible preventative effects of melatonin and Vitamin C on tympanosclerosis in rats by using histopathology and determination of total antioxidant status total antioxidant status. Methods: Standard myringotomy and standard injury were performed in the middle ear of 24 rats. The animals were divided into three groups: Group 1 received melatonin, Group 2 received vitamin C, and Group 3 received saline solution. Results: The mean values of total antioxidant status were similar in the all study groups before the treatment period. The mean values of total antioxidant status were significantly higher in the melatonin and vitamin C groups compared to control group but vitamin C with melatonin groups were similar after the treatment period (p < 0.001). Minimum and maximum wall thicknesses were lower in the melatonin and vitamin C groups compared to the control group but the differences were insignificant. Conclusion: Melatonin increases total antioxidant status level and might have some effect on tympanosclerosis that develops after myringotomy.

摘要引言：鼓室硬化症（tympanosclerosis）的发病机制目前尚未完全阐明。近期研究证实，氧自由基（free oxygen radicals）在鼓室硬化症的发生发展中扮演重要角色。褪黑素（Melatonin）与维生素C（Vitamin C）均为强效抗氧化剂，可直接与活性氧（Reactive Oxygen Species）发生相互作用，调控自由基介导的组织损伤。
研究目的：通过组织病理学检测与总抗氧化状态（total antioxidant status）测定，明确褪黑素与维生素C对大鼠鼓室硬化症的潜在预防作用。
研究方法：对24只大鼠的中耳实施标准鼓膜切开术及标准造模损伤，将实验动物分为三组：第1组给予褪黑素，第2组给予维生素C，第3组给予生理盐水溶液。
研究结果：治疗前，所有研究组的总抗氧化状态均值无显著差异；治疗后，褪黑素组与维生素C组的总抗氧化状态均值均显著高于对照组，但褪黑素与维生素C联合组的总抗氧化状态均值与其他两组无显著差异（p < 0.001）。褪黑素组与维生素C组的中耳壁最小及最大厚度均低于对照组，但组间差异无统计学意义。
研究结论：褪黑素可提升总抗氧化状态水平，或许对鼓膜切开术后继发的鼓室硬化症具有一定干预效果。