Pre-Exposure to Chronic Unpredictable Stress Suppresses the Chemopreventive Potential of Aloe Vera (Av) Leaf Gel Against 7,12-Dimethylbenz(a)anthracene (DMBA) Induced Carcinogenesis

AbstractThe present study evaluates the topical application of aloe vera (Av) leaf gel as a protective natural product against 7,12-dimethylbenz(a)anthracene (DMBA)-induced skin lesions in Swiss albino mice and as an antioxidant for the systemic toxicity of DMBA in the presence and absence of chronic unpredictable stress (CUS). Animals were randomized into seven groups and sacrificed after 16 weeks of treatment. Av gel application along with DMBA + 12-O-tetradecanoylphorbol-13-acetate (TPA) was found to be effective in reducing tumor incidence, cumulative number of papillomas, tumor burden and tumor yield when compared to untreated groups. Furthermore, topical treatment with Av gel significantly increased the overall in vivo antioxidant status of mice. Conversely, lipid peroxidation levels were significantly decreased in skin and circulation. However, pre-exposure to CUS followed by DMBA + TPA + Av gel application reduced the chemopreventive efficacy of Av gel as evidenced by increased tumor incidence, tu...