Capsazepine-mediated TRPV1 blockade impairs angiogenesis by attenuating autophagy in perforator flaps

Distal necrosis remains a common postoperative complication of perforator flaps, largely due to insufficient perfusion and inadequate angiogenesis in ischemic flap tissue. Transient receptor potential vanilloid type 1 (TRPV1) has been implicated in vascular regulation through calcium-dependent signaling pathways; however, whether pharmacological blockade of TRPV1 affects angiogenesis in perforator flaps remains unclear. In this study, capsazepine was used to pharmacologically block TRPV1 in a rat perforator flap model. The results showed that capsazepine treatment significantly reduced flap survival compared with vehicle treatment (64.5 ± 1.2 % vs. 79.0 ± 1.7 %) and impaired angiogenesis, as indicated by reduced vascular density and decreased expression of VEGF, eNOS, and MMP2. Capsazepine also reduced the phosphorylation of CaMKII, CaMKKβ, and AMPK, together with decreased Beclin1 expression, a reduced LC3-II/I ratio, and induced pro-apoptotic changes, as evidenced by increased Bax and cleaved caspase-3 expression and decreased Bcl-2 expression. Notably, pharmacological enhancement of autophagy with rapamycin reduced Bax expression and increased MMP2 expression. Collectively, these findings indicate that capsazepine-mediated TRPV1 blockade impairs perforator flap survival and angiogenesis, at least in part, through reduced CaMKII/CaMKKβ/AMPK activation and attenuation of autophagy. The rapamycin rescue findings position autophagy as an important functional intermediary between TRPV1-associated signaling and the regulation of apoptosis and angiogenesis in perforator flaps.