Topical C-Phycocyanin-Loaded Transfersomes Attenuate Early Proinflammatory Epidermal Remodelling in a DMBA/TPA-Induced Mouse Model of Skin Dysplasia

Background/Objectives: Cutaneous squamous cell carcinoma (cSCC) develops through inflammation-driven preneoplastic alterations characterized by epidermal hyperplasia, dysplasia, and increased proliferative activity. C-phycocyanin (C-PC) possesses antioxidant and anti-inflammatory properties; however, its topical potential to attenuate a tumour-promoting cutaneous microenvironment is limited by poor skin penetration. This study evaluated the effects of C-PC-loaded transfersomes in a 7,12-dimethylbenz[a]anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse model of skin carcinogenesis. Methods: Male BALB/c mice were assigned to six groups (n = 10 per group). Carcinogenesis was initiated with a single topical application of DMBA, followed by twice-weekly TPA application for 16 weeks. C-PC-loaded transfersomes (1 mg/mL or 10 mg/mL) were applied topically. Histopathological assessment included epidermal thickness, rete ridge depth, mitotic activity, mast cell density, and semi-quantitative scoring of hyperplasia, dysplasia, and inflammation. Ki-67 immunohistochemistry was used to evaluate basal and suprabasal proliferation. Results: Carcinogen exposure induced marked epidermal thickening, severe dysplasia, increased mitotic activity, elevated Ki-67 expression, and pronounced dermal inflammation. Treatment with C-PC-loaded transfersomes significantly reduced epidermal thickness, rete ridge depth, mast cell density, mitotic counts, and suprabasal Ki-67 index. The 1 mg/mL concentration demonstrated the most consistent attenuation of dysplasia severity and inflammatory changes. No adverse histopathological alterations were observed in internal organs. Conclusions: These findings indicate that transfersome-mediated topical delivery of C-PC attenuates early inflammation-driven epidermal remodelling and tumour-promoting alterations in experimental skin carcinogenesis, supporting its potential as a topical preventive strategy.