Nuclear factor erythroid 2-related factor 2 and choline acetyltransferase co-expression in rat spinal cord neurons after ischemia-reperfusion injury

Abstract

Spinal cord ischemia-reperfusion injury (IRI) results in overproduction of reactive oxygen species leading to tissue oxidative stress which impacts the neuronal network in the spinal cord as well as glial cells. We investigated the expression of Nuclear factor erythroid 2-related factor 2 (Nrf2) in neurons and glial cells after occlusion of the abdominal aorta followed by IRI as well as the time-dependent expression of Nrf2 in the same cells. The experimental method of transient aortic occlusion was carried out on rats by cross-clamping of the abdominal aorta for 45 minutes. The animals used for this study were sacrificed 1 h, 6 h, and 48 h after reperfusion to determine time-related changes of Nrf2 expression, as well as changes of astrocyte activity in the spinal cord. Immunofluorescence results showed an increase in the staining intensity of Nrf2 expression in the neurons following ischemia with highest intensity 48 h post-reperfusion and an increase in a number of reactive astrocytes. Western blot analysis showed that Nrf2 protein expression increased in a cytoplasmic and nuclear fraction as early as 1 h after reperfusion and remained active 48 h after, resulting in increased expression of the main Nrf2 target gene HO-1. In conclusion, substances that enhance expression of Nrf2 may have the potential to prevent cellular damage to the spinal cord caused by IRI.