Chemopreventive effect of green tea on 9, 12 dimethyibenz-[a]-Anthracene [DMBA]-induced hamster buccal pouch carcinogenesis

ABSTRACT

Oral cancer prevention using naturally occurring substances that could be included in diet consumed by humans, is gaining attention. Investigating the chemopreventive effect of green tea, through assessment of mutant p53 immunoexpression, in the hamster buccal pouch epithelium-induced carcinogenesis. Forty-five hamsters were divided into 3 groups. Group A was served as controls. In group B, left pouches of hamsters were painted with 0.5% Dimethylbenz-[a]-anthracene [DMBA], 3 times/week for 6 weeks. Hamsters of group C were given Epigallocatechin Gallate [EGCG]; five animals were sacrificed [Group C3], the remaining 20 were divided into 2 groups; group C1 was given EGCG and DBMA and group C2 was given DBMA only. All pouches were surgically excised, fixed, processed for H and E and mutant p53 immunohistochemical staining. Mutant p53 immunoexpression score was highly significant in group B, compared to group C1 which was given EGCG only. Administration of EGCG, before and in combination with the carcinogen [group C1] resulted in significantly decreased expression of mutant p53 parallel to decreased grades of dysplasia. Administration of EGCG alone for 2 weeks [group C3] showed negative mutant p53 expression. EGCG proved to be a chemopreventive and/or protective agent; through suppressing and/or retarding malignant transformation, reducing cell proliferation and inducing apoptosis. The apoptosis may be possibly through preventing p53 mutations