Expression of microRNAs differed in the omental adipose tissue of obese rats.

Objective: To establish obese rat models by high-fat diet, screen microRNAs by microarray in the omental adipose tissue, and find out differential expression of microRNAs in obese rats, for further understanding the role of microRNAs as regulating molecules in obesity-induced lipid metabolism disorders.

Methods: 40 male SD rats were randomly divided into normal diet group and high-fat diet group, respectively. After fed for 8 weeks, rats were weighted, measured length and other characteristics were observed. Eye blood was taken to test blood glucose level, blood lipids level, insulin level and other indicators. The omental adipose tissue was measured by electronic analytical scales and saved at -80°C liquid nitrogen. Fat cells were stained by oil red to observe their morphology under microscopy. The expression of microRNAs was screened by microarray, and verified by Real-Time PCR.

Results: After high-fat diet for 4 and 8 weeks, some fatty indicators changed, including increased body weight, omental fat weight, triglycerides, total cholesterol, low-density lipoprotein, blood glucose level and insulin level, and decreased high-density lipoprotein, and differential phenotype of fat cells. Besides, by microarray techniques and Real-Time PCR, 13 differential expression microRNAs were identified, including 7 up-regulated microRNAs (microRNA30a, microRNA7e, microRNA30c, microRNA335, microRNA103, microRNA107, microRNA139-5p), and 6 down-regulated microRNAs (microRNA494, microRNA140, microRNA342-5p, microRNA382, microRNA17-1-3p, microRNA92a).

Conclusion: Changes in the expression of microRNAs contribute to the pathogenesis of many diseases, including obesity disorders. These alterations can be due to various mechanisms, such as cell proliferation, apoptosis, migration, and differentiation, providing new therapies for diseases.