# Neutrophil extracellular traps-targeting therapy with deoxyribonuclease 1 reduces large vessel occlusion-induced downstream microvascular thromboinflammation in a rat model of stroke

## TL;DR

This study shows that DNase 1, which breaks down DNA from neutrophils, reduces brain damage and improves recovery in a rat model of stroke.

## Contribution

The study demonstrates that targeting neutrophil extracellular traps with DNase 1 can reduce microvascular thromboinflammation in stroke.

## Key findings

- DNase 1 significantly reduced infarct volume and improved neurological outcomes in stroke rats.
- DNase 1 treatment reduced blood-brain barrier disruption and brain edema.
- Thrombin-antithrombin complexes and fibrinogen deposits were lower in DNase 1-treated rats.

## Abstract

Neutrophil activation and neutrophil extracellular traps (NETs) participate in downstream microvascular thromboinflammation (DMT) and blood brain barrier disruption in acute ischemic stroke (AIS).

The aim of this study was to test whether deoxyribonuclease 1 (DNase 1) infusion, which cleaves extracellular DNA, could reduce DMT in a transient middle cerebral artery (MCA) occlusion stroke model in rats.

Eighteen rats were subjected to 120-minute transient MCA occlusion. DNase 1 (3 mg/kg, 20% intravenous, and 80% intraperitoneal injection) or vehicle were randomly infused 30 minutes after MCA occlusion. Main outcome criteria were the infarct volume assessed with magnetic resonance imaging, neurological disability, and the rate of hemorrhagic transformation measured at 24 hours. Brain DMT was assessed with biomarkers of platelet, coagulation, and neutrophil activation quantified in brain homogenates.

The infusion of DNase 1 significantly reduced the infarct volume (P = .024) and improved 24-hour neurological outcome (P = .031) compared with vehicle. Staining for fibrin(ogen) and citrullinated histones H3 colocalized with extracellular DNA in the occluded microvessels. Brain thrombin–antithrombin complexes and fibrinogen deposits were significantly reduced in DNase 1-treated rats compared with vehicle (P = .027 and P = .036, respectively). The blood brain barrier disruption assessed with brain immunoglobulin G measurement and brain edema were also reduced in DNase 1-treated rats (P = .015 and P = .031, respectively).

Our results confirm that NETs contribute to DMT during AIS and that early NET-targeting therapy may represent a new strategy to improve the clinical benefit of large vessel recanalization in AIS.

•Extracellular DNA worsens brain injury in stroke via downstream microvascular thrombosis (DMT).•Rats underwent transient middle cerebral occlusion treated with deoxyribonuclease 1 (DNase 1) or vehicle.•DNase 1 reduced brain damage and brain-blood barrier disruption by mitigating DMT.•DNase 1 shows promise clinically by reducing DMT and improving thrombolysis.

Extracellular DNA worsens brain injury in stroke via downstream microvascular thrombosis (DMT).

Rats underwent transient middle cerebral occlusion treated with deoxyribonuclease 1 (DNase 1) or vehicle.

DNase 1 reduced brain damage and brain-blood barrier disruption by mitigating DMT.

DNase 1 shows promise clinically by reducing DMT and improving thrombolysis.