Isoliquiritigenin Attenuates Neuroinflammation in Traumatic Brain Injury in Young Rats.

Inflammation and apoptosis play a critical role in the pathological progress of traumatic brain injury (TBI). Isoliquiritigenin is a bioactive component extracted from licorice roots, which possesses anti-inflammatory and anti-apoptotic properties. This study aims to investigate the potential effects of isoliquiritigenin on neuroinflammation in a rat model of TBI.The SH-SY5Y cells were subjected to cell injury induced by shear stress and the effect of isoliquiritigenin on cell apoptosis was measured. Male rats received a controlled cortical impact to induce TBI and were then treated with isoliquiritigenin (20 mg/kg). Brain edema and contusion volume were measured to assess brain damage. Morris water maze, the beam-balance test, and the beam-walk test were performed to evaluate the cognitive and motor functions.Levels of proinflammatory cytokines and apoptotic regulators were measured. Results showed that isoliquiritigenin reduced shear stress-induced cell apoptosis in vitro. In young rats subjected to TBI, treatment of isoliquiritigenin reduced brain damage and attenuated motor and cognitive impairments. Isoliquiritigenin also reduced the level of proinflammatory cytokines and Bax and increased Bcl-2 and Bcl-xL in TBI rats.These findings suggest that isoliquiritigenin possesses beneficial effects in TBI by inhibiting inflammation and apoptosis.