# A Novel Postconditioning Approach Attenuates Myocardial Ischaemia-Reperfusion Injury in Rats

## TL;DR

A new method of postconditioning in rats reduces heart damage caused by restoring blood flow after a blockage.

## Contribution

A novel balloon-based postconditioning approach is introduced for rodents to study IRI.

## Key findings

- The balloon method allowed precise control of coronary blood flow during postconditioning.
- Postconditioning reduced infarct size and cardiac apoptosis in rats with IRI.
- Bcl-2 levels increased while Bax and cleaved caspase-3 levels decreased after postconditioning.

## Abstract

Ischaemia-reperfusion injury (IRI) is the damage that
occurs when blood flow is restored to a tissue or organ after a period of
ischaemia. Postconditioning is a therapeutic strategy aimed at reducing the
tissue damage caused by IRI. Postconditioning in rodents is a useful tool to
investigate the potential mechanisms of postconditioning. Currently, there is no
convenient approach for postconditioning rodents.

Rats were
subjected to a balloon postconditioning procedure. A balloon was used to control
the flow in the vessel. This allowed for easy and precise manipulation of
perfusion. Evans blue and triphenyltetrazolium chloride (TTC) double staining
were used to determine the infarct size. Apoptosis in the myocardium was
visualised and quantified by terminal deoxynucleotidyl transferase dUTP nick end
labeling (TUNEL). Western blotting was performed to assess the expression of key
apoptotic proteins, i.e., B-cell lymphoma 2 (Bcl-2), Bcl-2 Associated X
(Bax), and cleaved caspase-3.

The balloon control approach to
postconditioning provided accurate control of coronary blood flow and simplified
the postconditioning manipulation. Infarct size reduction was observed in IRI
rats after post-conditioning. There was a decrease in cardiac apoptosis in IRI
rats after conditioning, as detected by TUNEL staining. IRI rats showed increased
Bcl-2 levels and decreased Bax and cleaved caspase-3 levels in the myocardium.

Postconditioning was successfully applied in rats using
this novel approach. Postconditioning with this approach reduced infarct size and
apoptosis in the area at risk.