Curcumin alleviates brain edema by lowering AQP4 expression levels in a rat model of hypoxia-hypercapnia-induced brain damage

The present study aimed to investigate the therapeutic effects of curcumin (CU) against brain edema in a rat model of hypoxia-hypercapnia (HH)-induced brain damage (HHBD). Male Sprague-Dawley rats were divided into five groups, including a control group and four treatment groups. The rats in the control group were raised under normal laboratory conditions and were injected with water, whereas the rats in the treatment groups were exposed to a low O(2)/high CO(2) environment simulating HH conditions, and were injected with water, CU, dimethyl sulfoxide (solvent control) or monosialoganglioside GM1. After 2 weeks, the morphological characteristics of the brain tissues were analyzed using optical and electron microscopy. In addition, aquaporin (AQP)-4 protein expression levels in brain tissue samples were analyzed using streptavidin-biotin complex immunohistochemistry and western blotting, and mRNA expression levels were detected using reverse transcription-quantitative polymerase chain reaction. Severe brain edema, tissue structure disruption and increased AQP4 expression levels were detected in the brain tissues of the HH rats. Conversely, the rats treated with CU or GM1 exhibited attenuated HHBD-induced brain edema and tissue structure disruption, and decreased mRNA and protein expression levels of AQP4. The results of the present study suggested that CU treatment was able to attenuate HHBD-induced brain edema by downregulating the expression levels of AQP4 in a rat model. Therefore, CU may be considered a potential therapeutic drug for the treatment of patients with brain edema.