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-100β 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-100β, 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-α, 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.