RESUMO
In the present study, we investigated the potential of opuntiol, isolated from Opuntia ficus-indica, against UVA radiation-mediated inflammation and skin photoaging in experimental animals. The skin-shaved experimental mouse was subjected to UVA exposure at the dosage of 10 J/cm2 per day for ten consecutive days (cumulative UVA dose: 100 J/cm2). Opuntiol (50 mg/kg b.wt.) was topically applied one hour before each UVA exposure. UVA (100 J/cm2) exposure induces epidermal hyperplasia and collagen disarrangement which leads to the photoaging-associated molecular changes in the mouse skin. Opuntiol pretreatment prevented UVA-linked clinical macroscopic skin lesions and histological changes in the mouse skin. Further, opuntiol prevents UVA-linked dermal collagen fiber loss in the mouse skin. Short-term UVA radiation (100 J/cm2) activates MAPKs through AP-1 and NF-κB p65 transcriptional pathways and subsequently induces the expression of inflammatory proteins and matrix-degrading proteinases in the mouse skin. Interestingly, opuntiol pretreatment inhibited UVA-induced activation of iNOS, VEGF, TNF-α, and COX-2 proteins and consequent activation of MMP-2, MMP-9, and MMP-12 in the mouse skin. Moreover, opuntiol was found to prevent collagen I and III breakdown in UVA radiation-exposed mouse skin. Thus, opuntiol protects mouse skin from UVA radiation-associated photoaging responses through inhibiting inflammatory responses, MAPK activation, and degradation of matrix collagen molecules.