Abstract
Neuregulin-1 (NRG-1) is reported to be cardioprotective through the extracellular-regulated protein kinase (ERK) 1/2 pathway in myocardial ischaemia-reperfusion injury (MIRI). NOX4-induced ROS activated NLRP3 inflammasome and exacerbates MIRI. This study aims to investigate whether NRG-1 can suppress NOX4 by ERK1/2 and consequently inhibit the NLRP3/caspase-1 signal in MIRI. The myocardial infarct size (IS) was measured by TTC-Evans blue staining. Immunohistochemical staining, real-time quantitative PCR (RT-qPCR) and Western blotting were used for detection of the factors, such as NOX4, ERK1/2, NLRP3, caspase-1 and IL-1β .The IS in the NRG-1 (3 μg/kg, intravenous) group was lower than that in the IR group. Immunohistochemical analysis revealed NRG-1 decreased 4HNE and NOX4. The RT-qPCR and Western blot analyses revealed that NRG-1 mitigated the IR-induced up-regulation of NOX4 and ROS production. Compared with the IR group, the NRG-1 group exhibited a higher level of P-ERK1/2 and a lower level of NLRP3. In the Langendorff model, PD98059 inhibited ERK1/2 and up-regulated the expression of NOX4, NLRP3, caspase-1 and IL-1β, which exacerbated oxidative stress and inflammation. In conclusion, NRG-1 can reduce ROS production by inhibiting NOX4 through ERK1/2 and inhibit the NLRP3/caspase-1 pathway to attenuate myocardial oxidative damage and inflammation in MIRI.