Spectrofluorimetric detection of DMBA-induced mouse skin carcinoma

Restraint stress abates the antioxidant potential of melatonin on dimethyl benz (a) anthracene (DMBA) induced carcinogenesis

Free radical involvement in initiation, promotion and progression of carcinogenesis, implicates that scavengers of free radicals may act as inhibitors in the carcinogenic process. Melatonin, an antioxidant was used in the present study to evaluate its effectiveness on skin carcinogenesis induced by DMBA both with and without chronic restraint stress (CRS). Fifty Swiss albino young male rats were divided into five groups of 10 rats each as controls, topical DMB alone, Pre CRS-DMBA, melatonin DMBA and Pre-CRS-DMBA-melatonin treated groups. After 18 weeks blood was collected along with liver and skin samples. These were used for antioxidant enzyme assay, DNA damage and fluorescent spectra analysis. Melatonin showed antioxidant potential in combatting DMBA induced skin carcinogenesis measured by free radical scavenging enzymes and in vivo antioxidant status, DNA damage. Sensitive detection of the DMBA induced micro biochemical changes was possible by fluorescent spectroscopy from the transformed ratio of fluorescent intensity (F1 530 nm/630 nm) otherwise found constant for normal tissues. By melatonin treatment this ratio was similar to control values. The decreased antioxidant biochemical parameters depicting oxidative stress were comparable to comet assay and fluorescent studies, endorsing the chemo-preventive efficacy of melatonin against skin carcinogenesis caused by DMBA. CRS pre-exposure diminished the chemo-preventive/antioxidant ability of melatonin and the results were same as DMBA alone treatment, showing stress affected both cancer development and chemoprevention. CRS decreased the antioxidant potential of melatonin. Hence, managing stress could be perceived in cancer chemoprevention. Further studies focusing on stress reduction are needed.

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

The 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, tumor burden, tumor yield and MDA levels accompanied by decrease in the enzymatic and nonenzymatic antioxidants. These observations were further supported by the results of fluorescent studies and comet assay. The study demonstrates a reduction in the antioxidant and antitumor potential of Av gel in presence of CUS thereby, signifying the need of stress reduction during cancer chemopreventive trials.

Erythrocyte Protoporphyrin Fluorescence as a Biomarker to Monitor the Anticancer Effect of Semecarpus Anacardium in DMBA Induced Mammary Carcinoma Rat Model

Endogenous fluorescence has been proposed as a means of aiding the diagnosis of various malignancies. It has been suggested that erythrocytes may be the carriers of fluorophors that accumulate in cancer tissue and may be useful in the diagnosis and treatment of malignancies. Hence, the present study was designed to explore the spectrofluorimetric analysis of blood components as a marker for the analysis of mammary carcinoma treatment and also to bring about the protective effect of the drug Semecarpus anacardium on oxidative stress mediated damage of erythrocytes. Fluorescence spectra of the blood components were studied and also the level of lipid per oxides and antioxidant enzymes status in erythrocytes were determined in DMBA induced mammary carcinoma rats treated with Semecarpus anacardium Linn nut milk extract. Fluorescence emission spectroscopy of blood components are altered under cancer conditions and the drug effectively ameliorated these alterations in mammary carcinoma induced rats. The drug also effectively reduced the oxidative stress induced erythrocyte damage thereby restoring the erythrocytes antioxidant status. These results suggest that erythrocytes may be the carriers of fluorophors that accumulate in cancer tissue and hence acts as new biomarkers for the diagnosis and treatment.