Combination of puerarin and tanshinone IIA alleviates ischaemic stroke injury in rats via activating the Nrf2/ARE signalling pathway

Context Puerarin (Pue) and tanshinone IIA (Tan IIA) are often used in combination in the treatment of cerebrovascular diseases. Objective To investigate the neuroprotective effect and synergic mechanism of Pue-Tan IIA on the treatment of ischaemic stroke (IS). Materials and methods IS was induced in rats by middle cerebral artery occlusion (MCAO). Rats were intraperitoneally injected with Pue (36 mg/kg), Tan IIA (7.2 mg/kg), or Pue-Tan IIA (36 and 7.2 mg/kg) for five times [30 min before ischaemia, immediately after reperfusion (0 h), 24, 48, and 72 h after reperfusion]. After administration, neurological function assessment and histological changes in the brain were performed. S-100 beta and NSE levels were measured to determine the severity of brain injury. Oxidative stress parameters and inflammatory mediators were measured. The proteins involved in Nrf2/ARE signalling pathway were determined by qRT-PCR and western blot. Results After administration, the neurological function scores, infarct volume, S-100 beta, and NSE levels were significantly reduced in MCAO rats, especially with Pue-Tan IIA treatment (p < 0.05). All treatments increased T-AOC, CAT, SOD, and GSH activities and reduced GSSG activity and MDA, TNF-alpha, IL-6, ICAM-1, and COX-2 levels in MCAO rats. Pue-Tan IIA significantly increased Nrf2 expression in the nucleus (1.81-fold) and decreased its expression in the cytoplasm (0.60-fold). Pue-Tan IIA significantly increased the expressions of HO-1 (1.87-fold) and NQO1 (1.76-fold) and decreased Keap1 expression (0.39-fold). Discussion and conclusions The combination of Pue and Tan IIA could alleviate ischaemic brain injury by activating Nrf2/ARE signalling pathway, providing an experimental basis for clinical applications.