CMS Alleviated Oxidative Stress, Inflammation and Apoptosis in the Retina of DR Rats
Further, we examined oxidative stress and inflammation in STZ rats. It was shown that compared with the sham-operated rats, the reactive oxygen species (ROS) and 3,4-methylenedioxyamphetamine (MDA) levels were significantly increased, while superoxide dismutase (SOD) level was decreased in the retinal tissue of rats injected with STZ, which could be blocked by co-treatment of CMS in a dose-dependent manner (Table 2). In addition, the results of RT-qPCR and western blot analysis suggested that compared with sham-operated rats, the expression of iNOS was notably increased in rats injected with STZ, which was inhibited by CMS in a dose-dependent manner (Figure 2A - B). Nitrite test showed that compared with sham-operated rats, the expression of NO was notably increased in rats injected with STZ, which was blocked by CMS in a dose-dependent manner (Figure 2C). According to the result of ELISA, compared with sham-operated rats, rats injected with STZ presented notably increased expression of interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), and C-reactive protein (CRP). And compared with rats injected with STZ, rats injected with CMS + STZ presented a significantly decreased expression of IL-6, TNF-α, and CRP, and the effect of CMS was dose-dependent (Figure 2D - F). Then cell apoptosis was detected by TUNEL, which found that apoptosis in rats injected with STZ notably increased when compared with sham-operated rats. And compared with rats injected with STZ, apoptosis in rats injected with CMS + STZ obviously reduced, and the effect of CMS was dose-dependent (Figure 2G). Besides, western blot analysis showed that the expression of apoptotic factors (Cyt-C and Caspase-3) in rats injected with STZ was higher than that in sham-operated rats. And compared with rats injected with STZ, rats injected with CMS + STZ showed a reduced expression of apoptotic factors (Cyt-C and Caspase-3), and the effect of CMS was dose-dependent (Figure 2H). Taken together, it was concluded that CMS was beneficial to alleviate the increased oxidative stress, inflammation and apoptosis in retina in the STZ rat model induced by DR.