Bradykinin Type 2 Receptor Deficiency Reshapes Acute Neuroinflammation and Improves Cell Survival after Ischemic Stroke in Diabetic Mice
摘要
Diabetes mellitus exacerbates cerebral ischemic damage by potentiating neuroinflammation. We hypothesized that activation of the bradykinin type 2 receptor, a mediator of inflammation and vascular dynamics, might be detrimental to ischemic injury development in diabetic animals. We monitored the acute phase of cerebral ischemia in type 1 diabetic mice, diabetic bradykinin type 2 receptor knock-out mice, and their non-diabetic controls using neurological assessment, magnetic resonance imaging, and a comprehensive immuno-histochemical and morphological analysis to quantify changes in microglial, neutrophil, and neuronal populations. Our findings reveal that bradykinin type 2 receptor deficiency ameliorates neurological deficit in non-diabetic mice, despite similar ischemic lesion volumes across all investigated groups. Furthermore, in non-diabetic animals, the bradykinin type 2 receptor plays a discernible role in edema resolution, neuroprotection, and regulation of microglial response to ischemia. However, diabetes, as a stroke comorbidity, alters the involvement of the bradykinin type 2 receptor in ischemic injury development. Bradykinin type 2 receptor-deficient diabetic animals demonstrate delayed microglial cell loss and reduced microglial reactivity following ischemia compared to diabetic animals with functional bradykinin type 2 receptors. The attenuated immune response is accompanied by a marked absence of infiltrating neutrophils within the ischemic territory and improved neuronal survival. This study demonstrates that diabetes profoundly modifies the role of bradykinin type 2 receptor in cerebral ischemic injury, influencing both acute neuroinflammation and cell survival. These findings support the potential of the bradykinin type 2 receptor as a therapeutic target for stroke in diabetic population, warranting further investigation.
Graphical Abstract