Effects of Usnic Acid on Apoptosis and Expression of Bax and Bcl-2 Proteins in Hippocampal CA1 Neurons Following Cerebral Ischemia-Reperfusion

Introduction: Cerebral ischemia-reperfusion causes complex pathological mechanisms that lead to tissue damage, such as neuronal apoptosis. Usnic acid is a secondary metabolite of lichen and has various biological properties including antioxidant and anti-inflammatory activities. This study aimed to investigate the neuroprotective effects of usnic acid on apoptotic cell death and apoptotic-related proteins (Bax and Bcl-2) in the CA1 area of the hippocampus following cerebral ischemia-reperfusion. Material & Methods: A total of 42 male Wistar rats were randomly divided into three groups (sham, ischemia-reperfusion, and ischemia-reperfusion+usnic acid). Ischemia was induced by occlusion of both common carotid arteries for 20 min. Usnic acid (25 mg/kg, intraperitoneally) was injected at the beginning of reperfusion time. The expression levels of Bax and Bcl-2 proteins were measured using the immunofluorescence method, and the rate of apoptotic cell death was determined using the TUNEL staining method. (Ethic code: IR.SHMU.REC.1397.186) Findings: In this study, cerebral ischemia increased apoptotic cell death in the CA1 area of the hippocampus. It was demonstrated that usnic acid significantly decreased apoptotic cell death by decreasing the expression of Bax pro-apoptotic protein and increasing the expression of Bcl-2 (anti-apoptotic protein). Discussion & Conclusion: It can be concluded that usnic acid has a neuroprotective effect against cerebral ischemia-reperfusion damages by reducing cell death.