Reduction of Intestinal Polyp Formation in Min Mice Fed a High-Fat Diet with Aloe Vera Gel Extract

Aloe vera gel supercritical CO2 extract (AVGE) has been shown to contain five phytosterols, reduce visceralfat accumulation, and influence the metabolism of glucose and lipids in animal model experiments. Recentepidemiologic studies have shown that obesity is an established risk factor for several cancers including colorectalcancer. Therefore, we examined the effects of AVGE on intestinal polyp formation in Apc-deficient Min micefed 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 thelatter 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 groupsevery day (except on Sunday) for 7 weeks at a dose of 3.75 and 12.5 mg/kg body weight, respectively. ND and HFDgroups received 0.5% CMC alone. Between weeks 4 and 7, body weights in the HFD and HFD+LAVGE groupswere reduced more than those in the ND group. However, body weights were not reduced in the HFD+HAVGEgroup. Mice were sacrificed at the end of the experiment and their intestines were scored for polyps. No significantdifferences 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+HAVGEgroup were significantly lower than those in the HFD group. We measured plasma lipid (triglycerides and totalcholesterol) and adipocytokine [interleukin-6 and high molecular weight (HMW) adiponectin] levels as possibleindicators of mechanisms of inhibition. The results showed that HMW adiponectin levels in the HFD group weresignificantly lower than those in the ND group. However, the levels in the HFD+HAVGE group were significantlyhigher than those in the HFD group. These results indicate that HAVGE reduced large-sized intestinal polypsand ameliorated reduction in plasma HMW adiponectin levels in Min mice fed HFD.