Effects of curcumin on levels of nitric oxide synthase and AQP-4 in a rat model of hypoxia-ischemic brain damage

This study examines the preventive and therapeutic effects of curcumin on brain edema after hypoxic-ischemic brain damage (HIBD) in a rat model. Male Sprague-Dawley rats were divided into four groups: a sham group (SH), a hypoxic-ischemic group (HI) without drug treatment, a hypoxic-ischemic group (CU) with curcumin injection, and a hypoxic-ischemic group with DMSO injection (solvent control, SC). HIBD treatment led to edema and ultrastructural changes in the hippocampus, increased the activity levels of nitric oxide synthase (NOS) in the brain (P<0.05), and raised the expression of water channel protein 4 (Aquaporin-4, AQP-4) in the blood-brain barrier (BBB) (P<0.05). Curcumin injection, but not the control DMSO injection, partially reversed HIBD-induced brain edema and morphological changes, as well as HIBD-induced increase in NOS activities and AQP-4 expression (P<0.05). In conclusion, our results showed that BBB ultrastructural changes may play an important role in the formation and development of brain edema after HIBD. Curcumin may protect the BBB ultrastructure and thus decrease brain edema following HIBD by down-regulating HIBD-induced increase in NOS activities and AQP-4 protein expression.