It was recently shown that Nigella sativa (N. sativa) extracts can exert significant modulatory effects on different pathological, toxicological and cytotoxic protocols in vitro and in vivo. The present experiment was designated to evaluate the candidate genes possibly involved with N. sativa inhibitory effects on colon carcinogenesis in post initiation phase. Twenty male rats were used; each administered two consequent injections of 1,3-dimethylhydrazine (DMH) (20 mg/kg BW) subcutaneously. The first group (10 rats) received 200 mg/kg of fresh N. sativa oil daily by intragastric gavage for eleven weeks after cessation of the carcinogen administration, while the second control group (10 rats) did not receive any treatment after DMH administration. Repeated genetic 3D-cDNA microarray analysis pointed out mainly 19 genes significantly changed in the colonic mucosa after N. sativa treatment either by up- or down-regulation. Interestingly, these genes encoding transcription factor activity, regulation of cell cycle, signal transduction, xenobiotic metabolism, apoptosis, DNA repair and lipid transport and metabolism. Real-time reverse transcription-PCR (RT-PCR) analysis confirmed the altered expressions of some dedicated genes after N. sativa treatment. These data point out to the involvement of N. sativa oil in many genetic pathways particularly those concerning cell cycle, apoptosis, DNA repair and xenobiotic metabolism in response to oxidative stress. These results could explain the genetic mechanism of action of N. sativa oil in inhibiting colon carcinogenesis in rats.
Key words: Nigella sativa, colon carcinogenesis, 3-D cDNA microarray, gene profiling, rat.
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