Aerobic Exercise Attenuates Epidermal Hyperplasia in an Obesity-Associated Psoriasiform Dermatitis Model

Obesity is an important risk factor for psoriasis, and clinical studies indicate that exercise interventions can improve disease severity. However, the mechanisms by which exercise influences psoriatic pathogenesis remain insufficiently understood. To investigate the effects of aerobic exercise on obesity-associated psoriasis, wild-type mice were fed a high-fat diet (HFD) for 7 weeks to induce obesity and subsequently underwent moderate-intensity treadmill running for 3 weeks. Psoriasiform dermatitis was induced by daily topical application of imiquimod (IMQ) to the skin for five consecutive days. HFD increased body weight, epididymal fat mass, and serum cholesterol. HFD-fed mice developed more severe IMQ-induced psoriatic skin changes compared with normal diet-fed mice. Treadmill exercise modestly reduced body weight gain and attenuated epidermal hyperplasia in HFD-fed mice. In contrast, inflammatory cytokine expression, including Tnfa, Il17a, and Il23a, showed modest increases in the skin of HFD-fed exercised mice, which did not parallel the improvement in epidermal hyperplasia. Overall, these findings indicate that while obesity exacerbates psoriasiform dermatitis, aerobic exercise ameliorates epidermal hyperplasia in obese mice without corresponding changes in inflammatory cytokine expression in the skin, suggesting that exercise may influence psoriatic skin changes through multiple metabolic and immunological pathways.