Source of Support: None, Conflict of Interest: None
Background: Adiponectin is an adipokines secreted by adipose cells and found to be lower in obese subjects than in lean subjects.
Aim: To examine potential anti-inflammatory effects of adiponectin on adipose tissue of animals on methionine-choline deficient diet.
Materials&Methods: 25 adult male albino mice were used in the study. The animals were divided into three groups: Group M1 animals (10 mice) were fed methionine-choline deficient diet for three weeks. On the third week, they were treated with intraperitoneal adiponectin injections (1.5 mg/kg/day. Group M2 animals (10 mice) were fed the same diet for three weeks. On the third week, they were treated with intraperitoneal 0.9% saline placebo injections. Control animals (5 mice) were fed regular chow for 3 weeks. The epididymal fat pad was bluntly dissected and transferred to fixative. It was prepared for routine paraffin sectioning and stained with H&E. The number of cells per mm2, adipocyte diameter and surface area were assessed using Image J Adipocytes Tool Macros.
Results: Adipocyte measurements were significantly reduced in both groups M1 and M2 in comparison to control animals. Fat sections from group M1 showed a marked reduction in fat cell size and tissue surface area with enlarged and congested blood vessels were surrounded by small rounded adipocytes and preadipocytes. Fat sections from group M2 animals showed an unusual picture of fatty microsyst formation, enlarged congested blood vessels surrounded by thick connective tissue cells mantle and in between the cysts, small fat cells and inflammatory infiltrate were observed. Some large cysts surrounded areas loaded with macrophages and preadipocytes at different stages of maturation.
Conclusion: The less amount of inflammation and absence of fatty microcysts in adiponectin treated animals suggests that adiponectin may have anti-inflammatory effects in rapidly remodeling adipose tissue.