The glycyrizin neuroprotective effects on the neurological scores, blood brain barrier permeability and brain edema after severe traumatic brain injury in male rat

Background and Aim : Traumatic brain injury (TBI) is one of the major causes of mortality and neurological disability . TBI has been classified into primary injury and secondary injury, and the latter plays a crucial role in the clinical outcome of patients with TBI. Glycyrrhizin (Gly) is a natural anti-inflammatory triterpene that largely exists in the roots and rhizomes of licorice. Recently, Gly has been found to be able to bind to HMGB1 and inhibit cytokine-like activities of HMGB1.Therefore, in this study, we investigated the effects of neuroprotective glycyrrhizin after traumatic brain injury in male ratsMethods : The male Albino wistar rats received different doses of glycyrrhizin (25, 50, 100 mg/kg, i.p.). All animals were intubated before surgery. In the TBI groups except sham and intact control groups, diffuse TBI was induced by Marmarou method using a TBI induction device. The severe TBI was induced using a weight 450 gr. The neurologic scores (VCS) and brain water content, the beam-walk –balance task (WB) and BBB integrity (Evans blue) were recorded for D1, D2 and D3 after TBI day. At the end of the third day from cisterna magna deep anaesthetized animals CSF was collected and then brain was removed and fixed in fluid nitrogen for H & D then analysis MMP-9 with Elisa assayResults : Our results showed a significant reduction in brain water content , blood brain barrier permeability and beam balance, and a significant increase in VCS and beam walk of treatment groups as dose response manner in compared to vehicle and TBI control groups (P<0.001). Glycyrrhizin in two dose (50 and 100 mg/kg) improved neurology, biochemistry and histological disorder but in 100 mg/kg dose results were better in compare with TBI-saline control groups (P<0.001)Conclusion : These findings showed that glycyrrhizin may implicate a critical role in promoting inflammation and aggravating damage after TBI. Post TBI administration revealed a delayed but significant improvement in histological and biochemestrical and neurological outcomes in experimental TBI. The underlying mechanism(s) was not determined and needs further investigation.

کلیدواژه ها:

Glycyrrhizin ، TBI ، neuroprotection ، blood brain-barrier ، rat