Objective To explore the effect of usnic acid on inflammatory injury in mice with intracerebral hemorrhage (ICH) based on high mobility group box 1 (HMGB1)/receptor for advanced glycation end products (RAGE) pathway. Methods C57BL/6 mice were randomly divided into sham group, model group, HMGB1 inhibitor ethyl pyruvate (40 mg/kg) group, usnic acid low-, high-dose (20, 30 mg/kg) groups and usnic acid (30 mg/kg) + rHMGB1 (8 μg/kg) group, with 18 mice in each group. The ICH model was constructed by intracranial injection of 0.5 μL collagenase. After continuous administration for 3 d, the modified neurological severity score (mNSS) and left turn rate of mice in each group were evaluated. The water rate of brain tissue in mice was determined. ELISA was used to measure the levels of interleukin-6 (IL-6), IL-1β and IL-18 in brain tissue. Hematoxylin-eosin (HE) staining was used to observe pathological changes in brain tissue. Immunofluorescence was used to observe microglia activation in brain tissue. TUNEL staining was used to detect cell apoptosis of brain tissue. Western blotting was used to detect the expressions of HMGB1/RAGE pathway related proteins in brain tissue. Results Compared with sham group, the striatum tissue of mice in model group was severely damaged, mNSS, left cerebral hemisphere water rate, ionized calcium-binding adapter molecule 1 (Iba1) positive cells number, inflammatory factors levels, cell apoptosis rate, HMGB1, RAGE, phosphorylated nuclear factor-κB p65 (p-NF-κB p65)/NF-κB p65 and TNF-α protein expression levels were significantly increased (P < 0.05), and the left turn rate was significantly decreased (P < 0.05). Compared with model group, the damage degree of striatum tissue in usnic acid low-, high-dose group and ethyl pyruvate group was alleviated (P < 0.05), mNSS, left cerebral hemisphere water rate, Iba1 positive cells number, inflammatory factors levels, cell apoptosis rate and HMGB1/RAGE pathway related proteins expression levels were significantly decreased (P < 0.05), and the left turn rate was significantly increased (P < 0.05). rHMGB1 significantly reversed the inhibitory effect of usnic acid on inflammatory injury in ICH mice (P < 0.05). Conclusion Usnic acid may alleviate inflammatory injury in ICH mice by inhibiting HMGB1/RAGE pathway.

usnic acid  /  high mobility group box 1  /  receptor for advanced glycation end product  /  intracerebral hemorrhage  /  inflammatory injury