Background:diabetes mellitus is a metabolic disorder in the endocrine system with a common biochemical manifestation, thus hyper-glycemia is a disturbed carbohydrate metabolism. This work aimed to evaluate the role of antidiabetic and hypoglycemic drug glibenclamide as a chemical agent and Aphanizomenon flos- aquae extract as a natural agent on lymphoid organs such as lymph nodes and spleen in the diabetic (type-2) white male albino rats.
Material and methods –Fifty male albino rats were used and categorized into five groups; group 1: control (C), group 2:Alloxan induced diabetic rats (D) (150 mg/kg b. wt); group 3:diabetic rats treated with daonil (D+Do)(daonil  5 mg/kg b.wt/day);  group 4:Aphanizomenon flos-aquae extract (AFA)(94.5mg/kg b.wt/day) and group 5:diabetic rats treated with Aphanizomenon flos -aquae extract(94.5mg/kg b.wt/day) (AFA+D). All groups were dissected after 30 days of treatment. Lymph nodes and spleen samples were taken for histological and histochemical studies. Blood samples were taken for measurement of serum glucose and serum insulin level. Results- Diabetic male rats showed very highly significant increase in the serum glucose level, while non significant increase was recorded in the other treated groups in comparison with the control group.Diabetic male rats showed highly significant decrease in the serum insulin level as compared to the control group. Conversely, treatment of diabetic rats with daonil showed   a significant increase in the levels of serum insulin. On the other hand non significant increase in the serum insulin was observed in AFA or AFA+D groups in comparison with the control group. Many histopathological and histochemical changes were observed in the lymph nodes and spleen of the diabetic rats, but using AFA extract succeeded to minimize the drastic changes which were observed in the lymph nodes and spleen of the diabetic rats more than that observed with glibenclamide. Conclusion- glibenclamide (daonil) as asynthetic drug and Aphanizomenon flos-aquae extract as a natural product ameliorated biochemical, histopathological and histochemical changes in the lymph nodes and splenic tissues of the diabetic rats.Aphanizomenon flos-aquae extract proved to be antidiabetic agent better than daonil drug and its antidiabetic action may be due to its anti-inflammatory, antioxidant and hypoglycemic action.