Exogenous Testosterone Inhibits Cutaneous Repair An A Murine Gender-Affirming Surgery Model

Wound healing problems are a major cause of morbidity for gender-affirming surgery (GAS) patients. Prior studies have shown sex differences in wound healing may exist. We hypothesized exogenous testosterone supplementation may impair post-GAS wound healing and developed a model to investigate this phenomenon.

Methods

Mice were randomized based on hormone regimen and gonadectomy (OVX). Gonadectomy or sham occurred on day 0 and mice were assigned to no testosterone (-T), mono- or bi-weekly (T/2T) testosterone groups. Dorsal splinted wounding occurred on day 14 and wound harvest on day 21. Serum testosterone levels were quantified with mass spectrometry. Wound tissue underwent analysis with planimetry, qPCR, ELISA and immunofluorescence.

Results

Mean testosterone trough levels for bi-weekly regimen were higher compared to mono-weekly (397ng/dL vs. 272ng/dL; p=.027). At POD5, 2T injections led to 24.9% and 24.7% increases in mean wound size relative to SHAM and OVX/-T, respectively (p=.004; .001). Wounds in OVX/+2T mice demonstrated increased gene expression for inflammatory cytokines (i.e., TNFa, VEGFa, TGFb1, MIF, Col-1, Col-3, aSMA) and macrophage marker F4/80 (p<.05). ELISA confirmed elevated wound TNFα levels (p<.05). Quantitative multiplex immunofluorescence with F4/80/NOS2/ARG1 showed significant increases in macrophage prevalence in OVX/+2T (p<.05).

Conclusions

We developed a novel model of the GAS hormonal milieu to study effects of exogenous testosterone on wound healing. Optimized twice-weekly dosing yielded serum levels comparable to clinical therapy. We show that exogenous testosterone administered to XX/OVX mice significantly impairs wound healing. A hyperinflammatory wound environment results with increased macrophage proliferation and elevated cytokines such as TNFα. Current efforts are directed towards mechanistic investigation and clinical validation. Preliminary results suggest differences in wound healing between castrated XX and XY mice treated with testosterone, suggesting not just a difference in hormone milieu but potentially a sex-based difference in wound healing response despite identical hormone profiles.