Chihara Takeshi, Shimpo Kan, Beppu Hidehiko, Tomatsu Akiko, Kaneko Takaaki, Tanaka Miyuki, Yamada Muneo, Abe Fumiaki, Sonoda Shigeru
Fujita Memorial Nanakuri Institute, Fujita Health University, Japan.
Asian Pac J Cancer Prev. 2013;14(7):4435-40. doi: 10.7314/apjcp.2013.14.7.4435.
Aloe vera gel supercritical CO2 extract (AVGE) has been shown to contain five phytosterols, reduce visceral fat accumulation, and influence the metabolism of glucose and lipids in animal model experiments. Recent epidemiologic studies have shown that obesity is an established risk factor for several cancers including colorectal cancer. Therefore, we examined the effects of AVGE on intestinal polyp formation in Apc-deficient Min mice fed a high-fat diet. Male Min mice were divided into normal diet (ND), high fat diet (HFD), low dose AVGE (HFD+LAVGE) and high dose AVGE (HFD+HAVGE) groups. The ND group received AIN-93G diet and the latter 3 groups were given modified high-fat AIN-93G diet (HFD) for 7 weeks. AVGE was suspended in 0.5% carboxymethyl cellulose (CMC) and administered orally to mice in HFD+LAVGE and HFD+HAVGE groups every day (except on Sunday) for 7 weeks at a dose of 3.75 and 12.5 mg/kg body weight, respectively. ND and HFD groups received 0.5% CMC alone. Between weeks 4 and 7, body weights in the HFD and HFD+LAVGE groups were reduced more than those in the ND group. However, body weights were not reduced in the HFD+HAVGE group. Mice were sacrificed at the end of the experiment and their intestines were scored for polyps. No significant differences were observed in either the incidence and multiplicity of intestinal polyps (≥0.5 mm in a diameter) among the three groups fed HFD. However, when intestinal polyps were categorized by their size into 0.5-1.4, 1.5-2.4, or ≥2.5 mm, the incidence and multiplicity of large polyps (≥2.5 mm) in the intestine in the HFD+HAVGE group were significantly lower than those in the HFD group. We measured plasma lipid (triglycerides and total cholesterol) and adipocytokine [interleukin-6 and high molecular weight (HMW) adiponectin] levels as possible indicators of mechanisms of inhibition. The results showed that HMW adiponectin levels in the HFD group were significantly lower than those in the ND group. However, the levels in the HFD+HAVGE group were significantly higher than those in the HFD group. These results indicate that HAVGE reduced large-sized intestinal polyps and ameliorated reduction in plasma HMW adiponectin levels in Min mice fed HFD.
芦荟凝胶超临界二氧化碳提取物（AVGE）在动物模型实验中已被证明含有五种植物甾醇，可减少内脏脂肪堆积，并影响葡萄糖和脂质代谢。最近的流行病学研究表明，肥胖是包括结直肠癌在内的几种癌症的既定危险因素。因此，我们研究了AVGE对高脂饮食喂养的Apc缺陷型Min小鼠肠道息肉形成的影响。将雄性Min小鼠分为正常饮食（ND）组、高脂饮食（HFD）组、低剂量AVGE（HFD+LAVGE）组和高剂量AVGE（HFD+HAVGE）组。ND组给予AIN-93G饮食，后三组给予改良的高脂AIN-93G饮食（HFD）7周。将AVGE悬浮于0.5%羧甲基纤维素（CMC）中，分别以3.75和12.5mg/kg体重的剂量，每天（周日除外）口服给予HFD+LAVGE组和HFD+HAVGE组小鼠7周。ND组和HFD组仅给予0.5%CMC。在第4至7周期间，HFD组和HFD+LAVGE组的体重下降幅度大于ND组。然而，HFD+HAVGE组的体重没有下降。实验结束时处死小鼠，对其肠道息肉进行评分。在喂食HFD的三组中，肠道息肉（直径≥0.5mm）的发生率和多发性均未观察到显著差异。然而，当将肠道息肉按大小分为0.5-1.4mm、1.5-2.4mm或≥2.5mm时，HFD+HAVGE组肠道中大型息肉（≥2.5mm）的发生率和多发性显著低于HFD组。我们测量了血浆脂质（甘油三酯和总胆固醇）和脂肪细胞因子[白细胞介素-6和高分子量（HMW）脂联素]水平，作为可能的抑制机制指标。结果显示，HFD组的HMW脂联素水平显著低于ND组。然而，HFD+HAVGE组的水平显著高于HFD组。这些结果表明，HAVGE减少了Min小鼠喂食HFD时的大型肠道息肉，并改善了血浆HMW脂联素水平的降低。
