Lipocalin 2 mediates kidney function abnormalities induced by ischemic stroke in mice: Involvement of neural pathways.

Background: Kidney function abnormalities is a common complication following ischemic stroke. Lipocalin 2 (LCN2) is currently a well-recognized specific biomarker of tubular injury. However, the role of LCN2 in kidney function abnormalities following stroke remains elusive. The sympathetic nervous system plays a crucial role in linking the brain and kidney. However, whether the kidney sympathetic nervous system regulates the expression of LCN2 following ischemic stroke has not been identified.

Methods: In this study, we established a middle cerebral artery occlusion (MCAO) model to induce ischemic stroke in mice. Renal function was assessed 24 h after cerebral ischemia-reperfusion injury. Transcriptomic sequencing of kidney tissue was performed to identify potential pathological mechanisms. The role of LCN2 in post-stroke renal injury was investigated using renal tubule-specific LCN2 knockout mice and a combination of qPCR, western blotting, immunofluorescence, and transmission electron microscopy. In addition, renal denervation (RDN) was used to explore the relationship between sympathetic nerves and the expression of renal LCN2.

Results: Ischemic stroke significantly exhibits renal functional impairment 24 h after reperfusion. Notably, RNA sequencing and Western blotting revealed a markedly increased expression of renal LCN2 following ischemic stroke. Renal tubular Lcn2-specific knockout significantly ameliorated the occurrence of kidney function abnormalities after stroke. Subsequently, we observed that the activation of renal sympathetic nerves upregulates LCN2 and induces kidney function abnormalities after stroke.

Conclusions: These findings reveal a neural pathway in which the sympathetic nervous system upregulates LCN2, providing potential therapeutic strategies for renal protection following ischemic stroke.