Abstract
Previous studies have demonstrated that ovariectomy may lead to a reduction in antioxidative biomarkers in the myocardium, thus suggesting that estrogens may serve a protective role in the suppression of oxidative stress. Lycium barbarum polysaccharides (LBP) are a well‑known antioxidant Chinese traditional medicine, which appear to have a similar function to estrogens with regards to the regulation of cardiac function. In the present study, 30 Sprague‑Dawley rats were randomly divided into the following groups: Sham operation group, ovariectomized (OVX) group, estradiol valerate group, high‑dose LBP (LBP‑H) group and low‑dose LBP (LBP‑L) group. All of the rats were provided tap water, estradiol valerate or LBP for 12 weeks. In addition, all rats were ovariectomized, with the exception of rats in the sham operation group, which underwent fat removal only. Reactive oxygen species (ROS), malondialdehyde (MDA), glutathione peroxidase (GSH‑px), catalase (CAT) and superoxide dismutase activities were subsequently examined. The protein expression levels of cleaved caspase‑9, cleaved caspase‑3 and phosphorylated‑protein kinase B (p‑Akt) were also assessed. The results demonstrated that high‑dose LBP decreased the enhanced levels of ROS and MDA in OVX rats, whereas GSH‑px and CAT activities were increased in the LBP‑H group compared with in OVX rats. Furthermore, the expression levels of cleaved caspase‑9 and cleaved caspase‑3 were significantly upregulated in the OVX group, whereas high‑dose LBP exerted protective effects on OVX rats by decreasing the expression of apoptotic proteins. Conversely, p‑Akt expression was decreased in the OVX group and was increased in the LBP‑H group. These results indicated that LBP is essentially involved in cardiac protection by inhibiting apoptosis in response to oxidative stress. In addition, improvement of antioxidant status by LBP is associated with the Akt signaling pathway in the myocardium of OVX rats.