Short-Term versus Long Term intermittent hypobaric hypoxia on cardiac fibrosis and cardioprotective effects of Natural antioxidants supplementation in rats hearts

摘要

Controversial effects of intermittent hypobaric hypoxia (IHH) such as cardiac damage or cardiac protection are still mysterious. It is unclear if short-term and long-term IHH challenges exert different changes of the pro-oxidant/antioxidant balance in the heart and throughout the body. It has been shown that natural antioxidants supplementation (Quercetin, Lycium barbarum and Chitosan) is effective in preventing the hypoxic stress. The aim of this study was to evaluate the protective effect of these natural antioxidants’ administration in heart in animals exposed to IHH and therefore exposed to oxidative stress. One hundred male Wistar rats were randomized assigned into ten groups was exposed to short-term and long-term IHH (380 mmHg, 12% O2, 8h/day) for different periods of time (2 days or 4 weeks) or kept in normoxia for 4 weeks. Some of the rats were administered natural antioxidants cu 30 minute before each IHH exposure of IHH. After short-term IHH or long-term IHH challenge, myocardial morphology was determined by histological analysis. Myocardial sections were examined histopathologically to determine the cardiomyocyte viability and morphometry. The results show a negative effect of IHH on the cardiomyocyte viability and cardio-protective effects of natural antioxidants’ administration. This study suggests that treatment with Quercetin, Lycium barbarum or Chitosan alone substantially restored the myocardial architecture and acted like cardioprotectants.