Objective: To observe the inhibitory effect of Shenbai Jiedu Fang (SBJDF, a compound recipe of traditional Chinese herbal drugs) on chemically induced carcinogenesis of colorectal adenoma in mice and explore the role of PTEN/PI3K/AKT signaling pathway in mediating this effect.
Methods: Four-week-old male C57BL/6 mice were randomly divided into control group (n=10), AOM/DSS model group (n=20), low-dose (14 g/kg) SBJDF group (n=10) and high-dose (42 g/kg) SBJDF group (n= 10). In the latter 3 groups, the mice were treated with azoxymethane (AOM) and dextran sodium sulphate (DSS) to induce carcinogenesis of colorectal adenoma. In the two SBJDF treatment groups, SBJDF was administered daily by gavage during the modeling. The survival rate, body weight, general condition of the mice, and intestinal adenoma formation and carcinogenesis were observed. The expressions of proteins associated with the PTEN/PI3K/AKT signaling pathway in the intestinal tissue were detected using immunohistochemistry.
Results: Compared with those in the model group, the mice treated with SBJDF, especially at the high dose, showed a significantly lower incidence of intestinal carcinogenesis and had fewer intestinal tumors with smaller tumor volume. Pathological examination showed the occurrence of adenocarcinoma in the model group, while only low-grade and high-grade neoplasia were found in low-dose SBJDF group; the mice treated with high-dose SBJDF showed mainly normal mucosal tissues in the intestines with only a few lesions of low-grade neoplasia of adenoma. Compared with those in the control group, the mice in the model group had significantly elevated plasma miRNA-222 level (P < 0.05), which was obviously lowered in the two SBJDF groups (P < 0.01). The results of immunohistochemistry revealed that compared with the model group, the two SBJDF groups, especially the high-dose group, had significantly up-regulated expressions of PTEN, P-PTEN and GSK-3β and down-regulated expressions of p-GSK-3 β, PI3K, AKT, P-AKT, β-catenin, c-myc, cyclinD1 and survivin in the intestinal tissues.
Conclusion: SBJDF can significantly inhibit colorectal adenoma formation and carcino-genesis in mice possibly through regulating miRNA-222 and affecting PTEN/PI3K/AKT signaling pathway.
目的: 探讨参白解毒方（SBJDF）对结直肠腺瘤形成及癌变的影响及其对PTEN/PI3K/AKT信号通路的调控作用。
方法: 将4周龄的雄性C57BL/6小鼠随机分为对照组（10只）、AOM/DSS模型组（20只）、参白解毒方低剂量组（14 g/kg，10只）和参白解毒方高剂量组（42 g/kg，10只）。除对照组外，其余各组采用AOM/DSS诱导小鼠结直肠腺瘤癌变模型，处理组于造模中给予参白解毒方灌胃干预。比较各组小鼠的生存率、体质量和生存状态，观察肠道组织腺瘤形成及癌变等病理情况，免疫组化检测肠道组织PTEN/PI3K/AKT信号通路相关分子的表达。
结果: 参白解毒方干预后小鼠的肿瘤发生率、数量和体积均显著低于AOM/DSS模型组，且高剂量的参白解毒方抑制效果更佳。HE病理切片结果显示模型组已形成腺癌，而参白解毒方可以抑制腺瘤的形成及癌变，参白解毒方低剂量组小鼠肠道同时存在腺瘤低级别瘤变和高级别瘤变，参白解毒方高剂量组小鼠肠道以正常粘膜组织为主，仅发现局部少量腺瘤低级别瘤变。机制研究发现模型组血浆中miRNA-222表达高于空白组（P < 0.05），用药各组miRNA-222的表达量较模型组下调（P < 0.01）；小鼠肠道组织免疫组化结果显示，与AOM/DSS模型组相比，参白解毒方处理后PTEN、p-PTEN、GSK-3β表达上调，且在低剂量组、高剂量组表达有依次递增趋势；p-GSK-3β、PI3K、AKT、p-AKT、β-catenin、c-myc、CyclinD1、Survivin表达下调，且在低剂量组、高剂量组表达呈递减趋势。
结论: 参白解毒方可以显著抑制小鼠结直肠腺瘤形成及癌变，其作用机制可能与调控miRNA-222及影响PTEN/PI3K/AKT信号通路有关。
Keywords: AOM/DSS murine mode; PTEN/PI3K/AKT signaling pathway; Shenbai Jiedu Fang; carcinogenesis; colorectal adenoma; miRNA-222.