Flavanoids Extracted from Onion Inhibited Activation of Microglia and Release of Proinflammatory Factors around the Hematoma in ICH Model Rats

OBJECTIVE: To study flavanoids extracted from onion (FEO) on the number of activated microglia and the release of proinflammatory factors in intracerebral hemorrhage (ICH) model rat at different time points, and to explore its possible mechanism for treating ICH. METHODS: Totally 100 Wistar rats were used for preparing ICH model, and ICH model was successfully established in 90 of them. The 90 rats were randomly divided into the sham-operation group (n =10) , the ICH group (n =40) , the FEO group (n =40). Totally 100 [L autoblood was injected from fixed position to rats in the ICH group and the FEO group during modeling. Meanwhile, FEO at 0. 2 mL/10 g was given to rats in the FEO group, twice daily. No drug intervention was given to rats in the ICH group and the sham-operation group. Each group was further sub-divided into 5 sub-groups according to different time points such as 6, 24, 48, 72 h, and 7 days. There were 8 rats in each sub-group of the ICH group and the FEO group, 10 groups in total. There were 2 rats in each subgroup of the sham-operation group, 5 groups in total. Neurological functions at different time points were observed by Garcia JH. The injury degree of brain tissue was observed at dif- ferent time points using HE staining. Activated microglia around hematoma were observed at different time points after ICH by using immunohistochemical staining. Expressions of TNF-α and IL-1 β at different time points after ICH was detected using ELISA. RESULTS: In the ICH group, degenerated and necrotic zone occurred around hematoma after injecting autoblood, cells were untidily arranged with irregular nucleus, partial nucleus were shrunken with lamellar interstitial edema of the medulla. As time went by, degenerated and necrotic zone was dilated; vacant zone occurred around cells; cells were unevenly distributed with reduced neuron numbers. Meanwhile, infiltration of lymphocytes and neutrophils occurred. In the FEO group after FEO intervention, necrotic cells were lesser, cell arrangement and nucleus morphology were obviously alleviated, and infiltration of inflammatory cells was reduced at corresponding time points. Compared with the sham-operation group, behavioral scores at 5 time points all decreased, the number of activated microglia was added, and expressions of TNF-α and IL-1 β in hematoma tissue increased in the ICH group (P <0. 01). Compared with the ICH group, behavioral scores at 48 and 72 h, as well as day 7 all increased, the number of activated microglia was reduced, and expressions of TNF-α and IL-1β in hematoma tissue decreased in the FEO group (P <0. 01). CONCLUSION: FEO using the ethanol reflux method could improve symptoms of ICH model rats possibly by inhibiting activation of microolia and the release of proinflammatory factors around the hematoma.