An injectable self-healing curcumin-sustained-release hydrogel for lower limb ischemia via autophagy inhibition by Atp6v0d2 downregulation

Although hydrophobic drugs demonstrate the promising therapeutic efficacy for peripheral artery disease in vitro, their in vivo performance is often hindered by low bioavailability due to inherent hydrophobicity. To address this, an injectable, self-healing and curcumin-sustained-release hydrogel (CGP hydrogel) using a gelatin/polyvinyl alcohol hydrogel (GP hydrogel) was developed. The CGP hydrogel effectively preserved the DPPH radical-scavenging activity of curcumin at room temperature. Meanwhile, in the murine hindlimb ischemia model, a single intramuscular injection of CGP following femoral artery ligation significantly improved the motor function of the ischemic limb compared to curcumin suspension. This superior therapeutic outcome is attributed to the sustained release of curcumin from the CGP hydrogel. Mechanistically, we found that CGP, but not GP, inhibited the expression of Atp6v0d2 in ischemic skeletal muscle cells and suppressed ischemia-induced autophagy. The inhibition of autophagy may mitigate tissue and cellular necrosis and promote the expression of Myogenin. Furthermore, CGP reduced the expression of pro-fibrotic factors such as Tgfb1 and Ctgf and prevented skeletal muscle fibrosis. In summary, the CGP hydrogel, through its sustained release of curcumin, inhibits ischemia-induced autophagy, alleviates necrosis and fibrosis in skeletal muscle tissue and preserves motor function in the ischemic limb.