# A modified surgical approach to induce circle Willis perforation in mice using the common carotid artery

## TL;DR

A new surgical method for inducing brain hemorrhage in mice is faster and preserves blood vessel structure compared to the traditional method.

## Contribution

A modified surgical approach using the common carotid artery for Circle of Willis perforation in mice is introduced.

## Key findings

- The CCA approach had a 100% success rate and shorter surgical duration than the ECA approach.
- ICP fluctuations and mortality rates were similar between the ECA and CCA groups.
- Neurological outcomes were worse in SAH groups compared to sham, but similar between CCA and ECA SAH induction.

## Abstract

The Circle of Willis perforation (cWp) mouse model is widely used in subarachnoid hemorrhage (SAH) research but involves sacrificing the external carotid artery (ECA), which may have a potential affect on the hemodynamic in the carotid arteries and cortical perfusion. We propose a modified approach using needle puncture via the common carotid artery (CCA) to preserve carotid vascular integrity. Twenty-seven C57BL/6 mice were randomly assigned into three groups and underwent cWp surgery in three procedures: sham (n = 3), ECA (n = 12), and CCA (n = 12). Surgical duration, success rate, intraoperative intracranial pressure (ICP) fluctuations, 24-hour mortality, and neurological deficits were assessed. The CCA approach achieved a 100% success rate and shorter surgical duration than the ECA approach (ECA 73 ± 18 vs. CCA 36 ± 10 min, P < 0.05). ICP fluctuations and mortality rates were comparable between the ECA and CCA groups (P > 0.05), indicating that the CCA approach shared a similar pattern with the ECA approach. Neurological outcomes were similar across SAH groups (CCA SAH induction and ECA SAH induction) but worse than sham (P < 0.05) in terms of body weight loss, open-filed test and Rotarod test performances. This modified cWp CCA approach, which preserves the carotid structures, helps eliminate hemodynamic bias and offers a potentially more efficient alternative with a shorter surgical duration compared to the classical ECA approach. It may prove to be a valuable option for broader application in SAH preclinical research.

The online version contains supplementary material available at 10.1038/s41598-025-97603-1.