Let-7a, mir-9, mir-132, and mir-218 microRNA Expression in the Dorsomedial and Ventromedial Hypothalamic Nuclei during Aging in Rats

The hypothalamus is involved in the regulation of biological rhythms, integration of autonomic, endocrine, and behavioral functions and may also contribute in aging development and control. MicroRNAs (miRNA)s participate in the control of different processes in the nervous system, including the control of hypothalamic functions. Expression of miRNA let-7a-5p, miR-9a-3p, miR-132-3p and miR-218a-5p was studied in the dorsomedial (DMH) and ventromedial (VMH) hypothalamic nuclei in young and aged rats of both sexes by real-time polymerase chain reaction (RT-qPCR) method. In the DMH, we observed statistically significant decrease of let-7a-5p, miR-9a-3p, miR-132-3p and miR-218a-5p expression in aged male rats and decline of miR-132-3p and miR-218a-5p expression in aged female rats. In the VMH of both sexes, we did not find statistically significant differences of let-7a-5p, miR-9a-3p, miR-218a-5p miRNA expression between young and aged animals. The expression of miR-132-3p significantly increased 1.7 times in male aged rats compared to young animals. Thus, aging is accompanies with the decreasing of miRNA in the DMH of aged rats. These new results expand our understanding of the mechanisms of aging through hypothalamic expression of miRNA.