RP105 Attenuates Ischemia/Reperfusion-Induced Oxidative Stress in the Myocardium via Activation of the Lyn/Syk/STAT3 Signaling Pathway.

Although our previous studies have established the crucial role of RP105 in myocardial ischemia/reperfusion injury (MI/RI), its involvement in regulating oxidative stress induced by MI/RI remains unclear. To investigate this, we conducted experiments using a rat model of ischemia/reperfusion (I/R) injury. Adenovirus carrying RP105 was injected apically at multiple points, and after 72 h, the left anterior descending coronary artery was ligated for 30 min followed by 2 h of reperfusion. In vitro experiments were performed on H9C2 cells, which were transfected with recombinant adenoviral vectors for 48 h, subjected to 4 h of hypoxia, and then reoxygenated for 2 h. We measured oxidative stress markers, including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, as well as malondialdehyde (MDA) concentration, using a microplate reader. The fluorescence intensity of reactive oxygen species (ROS) in myocardial tissue was measured using a DHE probe. We also investigated the upstream and downstream components of the signal transducer and activator of transcription 3 (STAT3). Upregulation of RP105 increased SOD and GSH-Px activities, reduced MDA concentration, and inhibited ROS production in response to I/R injury in vivo and hypoxia reoxygenation (H/R) stimulation in vitro. The overexpression of RP105 led to a decrease in the myocardial enzyme LDH in serum and cell culture supernatant, as well as a reduction in infarct size. Additionally, left ventricular fraction (LVEF) and fractional shortening (LVFS) were improved in the RP105 overexpression group compared to the control. Upregulation of RP105 promoted the expression of Lyn and Syk and further activated STAT phosphorylation, which was blocked by PP2 (a Lyn inhibitor). Our findings suggest that RP105 can inhibit MI/RI-induced oxidative stress by activating STAT3 via the Lyn/Syk signaling pathway.