Distribution features of HIF-1α- and HIF-2α-immunopositive neurons in the cerebral cortex in old rats after experimental myocardial infarction

Abstract

Objective. To conduct a comparative study of the quantitative content of HIF-1α- and HIF-2α-immunopositive neurons in the prefrontal cortex of the rat brain at different periods of experimental myocardial infarction (MI) development.

Materials and methods. In order to study the content of HIF-1α- and HIF-2α-positive neurons in the cerebral cortex of Wistar rats and 15, 30, and 45 days after MI, immunohistochemical methods were used.

Results. In rats of the control group, the HIF-1α and HIF-2α immunohistochemical markers in the prefrontal cortex are detected in few pale-colored neurons. On the 15th day after MI modeling, the number of HIF-1α-positive neurons increases by almost one third; on the 30th day, it reaches the maximum level. On the 45th day, the number of HIF-1α-positive structures decreases but remains above the control level, and the number of marked HIF-2α-structures reaches the highest values during this period.

Conclusion. Although the molecular structure of HIF-1α is similar to HIF-2α, each of the factors causes expression of different genes and different duration of adaptation of prefrontal cortex neurons to post-infarction hypoxia. HIF-1α appears to be responsible for the acute adaptation of cortical neurons to hypoxia, while HIF-2α is associated with long-term adaptation. In the period of the most pronounced decrease in  HIF-1α induction in cortical neurons, HIF-2α activation was observed, which indicates a time-coordinated involvement of both proteins in providing the systemic response of the organism.