Effect of Danggui Buxue decoction on hypoxia-induced injury of retinal Müller cells <i>in vitro</i>

Retinopathy is a common complication of diabetes mellitus and the leading cause of visual impairment. Danggui Buxue decoction (RRP) has been used as a traditional drug for the treatment of diabetic nephropathy for many years. The aim of this study was to investigate the effects of RRP on hypoxia-induced retinal Müller cell injury. A model of retinal Müller cell damage was created using high glucose levels (25 mmol/L) and/or exposure to low oxygen conditions (1% O2). RRP was given to rats by continuous gavage for 7 days to obtain drug-containing serum. After sterilization, the serum was added to the culture medium at a ratio of 10%. Cell viability, apoptosis, and cell proliferation were assessed using the CCK-8 kit, Annexin V-FITC/propidium iodide apoptosis kit, and EdU kit. The mRNA levels of angiogenesis factors (ANGPTL4, VEGF) and inflammatory factors (IL-1B, ICAM-1) were detected by RT-qPCR. Western blot analysis was employed to assess the levels of proteins related to the ATF4/CHOP pathway. Following hypoxia for 48 h and 72 h, there was a significant decrease in cell viability and proliferation, as well as a notable increase in apoptosis compared to the control group (21% O2). However, high glucose stimulation had no significant effect, and high glucose combined with hypoxia had no further damage to cells. After 48 h of exposure to low oxygen levels, the mRNA expression levels of ANGPTL4, VEGF, IL-1B, and ICAM-1 in retinal Müller cells were significantly higher than in the control group (21% O2). RRP treatment significantly alleviated the increase of cell apoptosis and the upregulation of IL-1B and-1 in retinal Müller cells induced by hypoxia. RRP has the potential to reduce the suppression of the ATF4/CHOP pathway in hypoxia-induced retinal Müller cells, and it significantly alleviates cell apoptosis through regulating inflammatory factors and the ATF4/CHOP pathway.