Immune injury in rat models of type 2 diabetes mellitus

Background: Diabetic cardiomyopathy is an important complication of type 2 diabetics. The role of immunoinflammation, immunity, and diet has not been adequately clarified. Objective: We investigated the relationships between diabetic cardiomyopathy and immuno-inflammation, as well as immunity and diets. Methods: Sixty Sprague-Dawley (SD) male rats were included in this study, from which 12 were randomly selected as the normal control group (group A) and of which the remaining 48 were considered as the type 2 diabetes mellitus (T2DM) model group. Group A was fed with common diets and the T2DM model group, with high-glucose diets (by adding 20% cane sugar, 10% lard, and 2.5% cholesterol into a 67.5% common diet). After 4-week feeding, the T2DM model group was randomly allocated into three groups according to the diet, high-fat diet group (group B), common diet group (group C), and low-fat diet group (group D). All the three groups were then fed for another 10 weeks. At the end of the experiment, body weight, random blood glucose levels, and cardiac weight were measured. Left ventricular tissue was obtained for light microscopy and electron microscopy. Deposits of immunoglobulin G (IgG) in myocardium were identified by immunohistochemistry. Serum levels of high-sensitivity C-reactive protein (hs-CRP) were determined using the enzyme-linked immunosorbent assay (ELISA). All data were statistically analyzed. Results: The serum level of hs-CRP was significantly higher in groups B, C, and D, than in the control group. Therefore, IgG deposits among cardiac muscle cells were observed in all the model groups, significant deviations were noted in group A (p < 0.01) and IgG deposits were less in group D than in groups B and C (p < 0.01). Conclusion: Immuno-inflammation participates in the development of T2DM and diabetic cardimyopathy. Immune injury can be alleviated following dietary interference.