RESUMO
This study was designed to evaluate the possible role of Nigella sativa L. [NS] oil, as chemopreventive agent against DMBA- induced hamster buccal pouch [HBP] carcinogenesis. This study was carried-out on eighty-five male golden Syrian hamsters divided into nine main groups. In animals of DMBA-treated groups the left buccal pouches were painted with 0.5% DMBA, 3 times/week. Animals of NS-treated groups, were given 5 mgs/day of NS oil orally. Other groups were given both NS and DMBA at the same time, 3 times/week for 6 weeks. The animals were sacrificed by inhalation of high dose of ether. Both buccal pouches were surgically excised fixed in 10% neutral buffered formaline, and processed for H and E and p53 immunohistochemical stains. Topical application of DMBA in HBP, produced different grades of epithelial dysplasia, and over-expression of mutant p53. Administration of NS oil, inhibited the development of advanced dysplastic changes, and decreased expression of mutant p53. These findings suggest that NS oil is a potential retarding agent of DMBA-induced HBP carcinogenesis through down-regulating mutant p53 expression