# Proteomic analysis of heparin amelioration of cardiac injury after CA-CPR in rats: an exploratory proteomic study

## TL;DR

This study explores how heparin may protect the heart after cardiac arrest in rats by analyzing changes in heart proteins.

## Contribution

The study provides new insights into heparin's potential myocardial protective mechanisms beyond anticoagulation using proteomic analysis.

## Key findings

- Heparin intervention improved pathological changes and reversed autophagy-related protein expression in cardiac tissues.
- Proteomic analysis identified 23 proteins with significant expression changes after heparin treatment.
- Heparin modulated the expression of IDH3A and RPTOR, proteins linked to mitochondria and autophagy.

## Abstract

Patients who recover from cardiac arrest with autonomous circulation often have a poor prognosis due to myocardial dysfunction. Heparin, a pleiotropic drug, has not yet been identified for its myocardial protection mechanism in addition to anticoagulation. The aim of this study was to investigate the potential molecular mechanism by which heparin ameliorates cardiac injury after CA-CPR in rats via proteomic techniques.

A rat asphyxiated CA-CPR model was established, and the rats were randomly divided into a sham operation group (Sham), a CA-CPR + normal saline group (NS) and a CA-CPR + heparin (H) intervention group. Myocardial histopathological changes were observed via HE staining, serum CK-MB levels were detected to assess the degree of myocardial injury, ultrastructural changes in cardiomyocytes were observed via transmission electron microscopy, and autophagy-related protein expression levels were detected via Western blotting. Data-independent acquisition (DIA) proteomics technology was used to analyze the differentially expressed proteins (DEPs) in the myocardial tissues of the three groups of rats, and GO functional annotation and KEGG pathway analysis were performed on the DEPs. Finally, Western blotting was used to verify the differential protein expression associated with mitochondria and autophagy.

Compared with those of the rats in group Sham, the myocardial tissues of the rats in group NS presented obvious pathological damage, with significantly elevated serum CK-MB and cTnI levels, severe damage to the ultrastructures of the cardiomyocytes, and decreased expression of autophagy-related proteins. Heparin intervention significantly improved these pathological changes and reversed the changes in the expression of some autophagy-related proteins. Proteomic analysis identified 6,002 proteins in total. When comparing NS vs. Sham groups, 198 proteins were differentially expressed (120 upregulated, 78 downregulated), while HP vs. NS comparison revealed 141 differentially expressed proteins (48 upregulated, 93 downregulated). Among these, 23 proteins showed significant expression changes both after CA-CPR and after heparin intervention. GO functional annotation and KEGG pathway analysis suggested that 5 proteins were potentially elated to autophagy. Western blot validation indicated that heparin intervention modulated the protein expression of IDH3A and RPTOR.

This exploratory proteomic study suggests via proteomics the changes in myocardial protein expression network in heparin-attenuated cardiac injury in CA-CPR rats. This exploratory proteomic study provides preliminary evidence for heparin treatment of myocardial injury after CA-CPR. These findings are hypothesis-generating and require validation in larger cohorts and multi-time-point follow-up studies.