Objectives High-mobility group box 1 (HMGB1), a nuclear protein, has been recently reported to attenuate cardiac remodelling following myocardial infarction (MI). This study was designed to investigate whether this effect could be strengthened by local intramyocardial injection of HMGB1 along with a novel Dex-PCL-HEMA/PNIPAAm hydrogel and ascertain its possible mechanism of action.

Methods Rat models were induced by coronary artery ligation. Phosphate buffered solution (PBS), Dex-PCL-HEMA/PNIPAAm hydrogel, HMGB1 in PBS, or HMGB1 in hydrogel was injected into a peri-infarcted area of cardiac tissue immediately following MI.

Results The injection of HMGB1 along with hydrogel improved cardiac function and reduced collagen content. Additionally, the number of c-Kit⁺/Ki67⁺, α-sarcomeric⁺/MEF2C⁺ and α-sarcomeric⁺/Ki67⁺ cells were increased significantly compared with the results of using either agent alone.

Conclusions HMGB1 injection with Dex-PCL-HEMA/PNIPAAm hydrogel attenuates cardiac remodeling and improves cardiac function after myocardial infarction by inducing myocardial regeneration.