Cardioprotective and Antihypertensive Effects of Topical Capsaicin in a Rat Model

TRPV1 regulates neuronal and vascular function mediated by NO and CGRP. Systemic arterial hypertension (SAH) induces an imbalance in vascular mediators NO and CGRP by altering the transport of Ca²⁺ ions through TRPV1, generating cellular damage. We studied the effect of topical capsaicin (CS) treatment on cardiac mechanical work, oxidative stress (TAC, NO, BH4, and BH2), cellular damage (MDA, MTO, and 8HO2dG), and inflammation (IL-6 and TNFα), generated by SAH, which was induced by L-NAME, in male Wistar rats. CS was added to a moisturizing cream and applied to the abdomen of animals for two weeks. Experimental groups were as follows: (1) Control, (2) Control+Cream, (3) Hypertensive, and (4) Hypertensive+Cream. Hearts were exposed to ischemia-reperfusion (I-R) using the Langendorff technique to study the potential cardioprotection of CS. Expression of SOD1, SOD2, catalase, eNOS, pNOS, TRPV1, and CGRP in cardiac tissue was evaluated. In the Hypertensive group, TRPV1 activation by CS (Hypertensive+Cream) reduced oxidative stress (OS), decreasing cellular damage and inflammation and increasing TAC, modulating biochemical and tissue alterations induced by OS generated by SAH. In parallel, an increase in tissue levels and the expression of CGRP, TRPV1, and eNOS, induced by CS, was observed. These findings indicate that pretreatment with CS attenuates cardiac I-R and SAH injury in rats. The cardioprotective mechanism may be based on TRPV1-mediated CGRP overexpression.