Quercetin promotes neuronal and behavioral recovery by suppressing inflammatory response and apoptosis in a rat model of intracerebral hemorrhage.

Intracerebral hemorrhage (ICH) is a common and devastating disease affecting millions of people worldwide annually. Exaggerated inflammation and apoptosis are two pivotal pathological processes for secondary brain injury after ICH. Quercetin, a flavonoid widely distributed in various herbs, fruits and vegetables, has been proved to improve neuronal functional recovery in spinal cord injury rats. However, the efficacy of quercetin in caring for post-ICH brain injury has not been investigated. In the present study, we established an ICH model by injecting type VII bacterial collagenase (0.5U) into the central striatum of male Sprague-Dawley rats. The animals were randomized to four groups: sham-operation group; ICH + vehicle group; ICH + 5 mg/kg quercetin group; and ICH + 50 mg/kg quercetin group. The expression levels of IL-1β, IL-4, IL-6 and TNF-α in the brain tissue were assayed by Real-time PCR, ELISA and Western Blot, and cell apoptosis was assayed by TUNEL and caspase-3 staining 3 days after model establishment. It was found that the lesion volume, the brain water content, the expression levels of the four inflammation markers and the number of apoptotic cells were reduced significantly in ICH rats receiving quercetin, especially in 50 mg/kg quercetin group. These results confirmed the therapeutic efficacy of quercetin in repairing brain injury, probably by inhibiting inflammatory response and apoptosis, thus promoting nerve functional restoration.