Propolis ameliorates cerebral injury in focal cerebral ischemia/reperfusion (I/R) rat model via upregulation of TGF-β1

Neuroprotective impact of transforming growth factor β1 (TGF-β1) is increasingly recognized in different brain injuries. Propolis exhibits a broad spectrum of biological and pharmacological properties including neuroprotective action. The objective of the investigation was to explore the involvement of TGF-β1 signaling in the neuroprotective mechanism of propolis in I/R rats. In this study, focal cerebral ischemia model was built by middle cerebral artery occlusion (MCAO) for 2 h followed by reperfusion. The investigation was carried out on 48 rats that were arranged into four groups (n = 12): the sham group, I/R control group, I/R + propolis (50 mg/kg) group and I/R + propolis (100 mg/kg) group. The results revealed that propolis preserved rats against neuronal injury induced by cerebral I/R. It significantly reduced neurological deficit scores and improved motor coordination and locomotor activity in I/R rats. Propolis antagonized the damage induced by cerebral I/R through suppression of malondialdehyde (MDA) and elevation of reduced glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), brain-derived neurotropic factor (BDNF) and dopamine levels in the brain homogenates of I/R rats. Other ameliorations were also observed based on reduction of neurodegeneration and histological alterations in the brain tissues. These results also proposed that the neuroprotective effect of propolis might be related to upregulation of TGF-β1 and suppressed matrix metallopeptidase-9 (MMP9) mRNA expression.