Beneficial Effects of Immunotherapy with Extracts Derived from Actinomycetales on Rats with Spontaneous Obesity and Diabetes

Abstract

To determine whether immunotherapy with heat-killed, selected Actinomycetales species could influence the progression of spontaneous Type 2 diabetes mellitus and obesity in a rat model. Preparations of either Gordonia bronchialis, Tsukamurella inchonensis or a saline placebo were given by three subcutaneous injections, 30 days apart, starting when rats were aged 120 days, just before development of Type 2 diabetes mellitus, and at day 440, when the disease was well established. Bodyweight, blood sugar, cholesterol, triglycerides and insulin levels were measured to determine the effects and at the end of the experiments, animals were subjected to necropsy. The development of Type 2 diabetes mellitus was prevented by both reagents, most effectively by T. inchonensis. In the treatment experiment, the effects of the disease were reduced by both treatments, markedly so by T. inchonensis. In both experiments obesity was reduced in treated animals. The possible mechanisms of action are discussed. Our findings suggest that Type 2 diabetes mellitus in the studied rats is associated with obesity, and that both diabetes and obesity can be prevented or improved by treatment with Actinomycetales immune modulators.