Fig. 7. The schematic diagram of the SrCO₃/HSA hydrogels in myocardium repair after I/R.

Various underlying mechanisms contributed to myocardial repair for SrCO₃/HSA hydrogels after I/R: (i) SrCO₃/HSA hydrogels sustain the release of Sr ions in the infarct heart; (ii) Sr ions inhibit the apoptosis of CMs through reducing the activity of caspase-3; (iii) Sr ions promote angiogenesis via increasing proliferation, strengthening paracrine capacity, and stimulating the interaction of cardiac cells. Ultimately, alleviative fibrosis and elevated cardiac function are achieved after the treatment of SrCO₃/HSA hydrogels. ECs, endothelium cells; SMCs, smooth muscle cells; Fbs, fibroblasts.