RESUMO
The increasing prevalence of diabetes mellitus in the world is of great concern. As synthetic drugs have undesirable side effects or contraindications, traditional medicinal plants are being used for treatments of diabetes. This study aimed to determine the protective effect of aloe vera [AV] on beta cells of diabetic rats. Forty adult male rats were utilized and divided equally into four groups. The first served as the control group; the second was the streptozotocin [STZ] group [single intraperitoneal dose of 65 mg/kg body weight]; the third was the preventive AV group, which was given a daily oral dose of AV [300 mg/kg body weight/day] for 14 days along with a single intraperitoneal injection of STZ given after 7 days from the start of AV; the fourth group was the curative AV group, which was given a single intraperitoneal injection of STZ and after 7 days were given a daily oral dose of AV for 14 days. Pancreatic tail samples were taken 14 days after the treatment with AV. Paraffin sections were prepared for histological and immunohistochemical studies. The results revealed that a single dose of STZ induced marked cytoplasmic vacuolations and pyknotic nuclei in many islet cells. The AV preventive group showed normal-appearing islet cells. The AV curative group showed cytoplasmic vacuolations and pyknotic nuclei in many islet cells. Statistical analysis revealed a significant decrease [P<0.05] in anti-insulin antibody reaction and bcl2 expression in the diabetic group and the AV curative group compared with the control group, whereas there was an insignificant increase in the preventive group. The present study suggests that AV when used as a preventive agent can protect against STZ-induced diabetes in rats. Therefore, AV should be given to prediabetic patients and to individuals at high risk for diabetes