姜黄素和儿茶素联用对二甲基肼诱导的大鼠大肠癌变过程中环氧合酶2表达的影响

目的探讨姜黄素和儿茶素联用对二甲基肼(DMH)诱导的大鼠大肠隐窝异常病灶(aberrant crypt foci，ACF)的数量及其对大鼠大肠组织环氧合酶2(cyclooxygenase-2，COX-2)表达的影响，方法利用DMH诱导大鼠大肠癌模型，研究姜黄素、儿茶素单独及联合应用对诱癌初期大鼠大肠ACF数量和对大鼠大肠癌发生的影响。同时应用RT-PCR方法检测了姜黄素和儿茶素对大鼠大肠癌变早期肠粘膜和癌瘤形成后肿瘤组织COX-2mRNA表达的影响。结果与阳性对照组相比，姜黄素和儿茶素和两者联用均可以显著抑制DMH诱导的大鼠ACF的数量和大鼠大肠癌的发生．两者联用的抑制作用明显高于两药单独应用。DMH可以诱导大鼠大肠组织COX-2mRNA的表达。姜黄素和儿茶素联用对抑制诱癌早期大鼠肠粘膜COX-2mRNA的表达有协同作用，但对大肠癌形成后肿瘤组织COX-2mRNA的表达无明显抑制作用。结论姜黄素和儿茶素联合应用对抑制DMH诱导的大鼠大肠癌的形成有协同作用，这种作用可能主要是通过抑制诱癌早期ACF的数量和COX-2mRNA的表达实现的。

Effects of combined use of curcumin and catechin on cyclooxygenase-2 mRNA expression in dimethylhydrazine-induced rat colon carcinogenesis]

OBJECTIVE: To examine the effect of combined use of curcumin and catechin on the number of aberrant crypt foci (ACF) and expression levels of cyclooxygenase-2 (COX-2) mRNA in rat colon carcinogenesis. Methods Dimethylhydrazine (DMH)-induced rats colon carcinogenesis model was used for evaluation of the synergistic inhibitory effect between curcumin and catechin in light of ACF formation and tumor incidence. COX-2 mRNA expression was also detected in rat colon carcinogenesis. RESULTS: Curcumin, catechin and their co-treatment caused significant inhibition of DMH-induced ACF and colon carcinogenesis as compared with untreated DMH-induced rat models (P<0.01). Co-treatment with curcumin and catechins caused greater inhibition of DMH-induced ACF and colon carcinogenesis than the single use of curcumin or catechin (P<0.05). A synergistic inhibitory effect between curcumin and catechin on the expression of COX-2 mRNA was observed in the early stage of rat colon carcinogenesis but not in colon tumor tissues. CONCLUSION: Curcumin and catechin have synergistic effect on ACF and COX-2 mRNA expression in rat colon carcinogenesis, suggesting their potential value in the prevention of human colon cancers.