Expression of miR-15b, miR-29b, miR-219 and miR-222 microRNAs in rats with focal cerebral ischemia submitted to physical exercise

Cerebral ischemia is one of the main causes of death in Brazil, according to a survey by the Brazilian Society of Neurology in 2000, being the third cause of death after cardiovascular diseases and cancer; it is also one of the major causes of permanent sequels that can result in disability. In the last decades, experimental studies have shown beneficial effects of physical exercise associated with cerebral ischemia. Several molecular mechanisms are involved in the pathophysiology of cerebral ischemia, including changes in neurotransmitter expression profiles. Current research has highlighted the role of microRNAs both in the process of cerebral ischemia and in the regulation of neurotransmitters. Therefore, analyzing the expression of neurotransmitters and microRNAs associated with cerebral ischemia, as well as the role of the benefits promoted by physical exercise may contribute to the elucidation of possible molecular pathways with neuroprotective effect. Forty-eight rats were divided into four experimental groups: control, cerebral ischemia through middle cerebral artery occlusion, physical exercise and physical exercise associated with cerebral ischemia. Real-time PCR methodology was used to analyze miRNA expression of miR15b, miR-29b, miR-219 and miR-222. We did not observe significant differences in miRNA expression in brain tissue in rats submitted to cerebral ischemia, physical exercise and both treatments when compared with the control group. However, miR-222 expression increased in the cerebral ischemia group submitted to physical exercise, which may help promote cerebrovascular regeneration.