###### Abstract  
Injectable decellularized matrix hydrogels derived from either myocardium or small intestinal submuc (pDMYO-gel, pDSIg-gel) have been successfully used for myocardial injury repair. However, the relationship between tissue-specific biological functions and protein composition in these two materials is not clear yet. In this study, the protein composition, mechanical properties, and morphology of these two hydrogels and their effects on the behavior of neonatal rat cardiomyocytes (NRCMs) and human umbilical vein endothelial cells (HUVECs), are investigated. The results show that pDMYO-gel is more conducive to growth, adhesion, spreading, and maintenance of normal NRCM beating, due to its higher proportion of extracellular matrix (ECM) glycoproteins (49.55%) and some unique functional proteins such as annexin-6 (ANXA6), agrin (AGRN), cathepsin D (CTSD) and galectin-1 (LGALS1), whereas pDSIg-gel is more conducive to the proliferation of HUVECs. Animal study shows that pDMYO-gel has a better effect on improving cardiac function, inhibiting myocardial fibrosis and maintaining ventricular wall thickness in acute myocardial infarction models in vivo. Therefore, it is proposed that injectable pDMYO-gel hydrogel may be more suitable for functional recovery of myocardial injuries. decellularized matrix hydrogels; protein composition; cardiomyocytes; proteomic analysis; myocardial infarction +
Footnote †: journal: Medical  
focus on tissue-derived decellularized matrices [12]. Porcine decellularized small intestinal submuca matrix (pDSIS), porcine decellularized myocardial matrix (pDMYO), and human decellularized amniotic membrane/human decellularized placenta (HDAM/HDP) matrices have been used to repair myocardial infarction [9; 10; 11; 13]. Two of them, pDSIS myocardial patch (CorMatrix(tm)) and pDMYO injectable hydrogel (Ventrigel(tm)), have already been commercialized. There are unique advantages in clinical application for injectable hydrogels since they can be directly injected into the injured site through minimally invasive surgery and form hydrogel in situ. Several studies demonstrated in different animal models that decellularized matrix hydrogels derived from diverse tissues can effectively repair myocardial injuries. [PERSON] et al. [9] prepared pDSIS hydrogels to repair porcine myocardial infarction and found that, compared with untreated animals, the cardiac functions of treated pigs, including ejection fraction and end systolic volume, were significantly improved. [PERSON] et al. [10] used HDP hydrogel to repair acute myocardial infarction in rats. Compared with that of control animals injected with a saline solution, the scar tissue of myocardial infarction area in treated animals was significantly reduced, and the surviving tissue maintained normal electrophysiological activity. [PERSON] et al. [11] prepared pDMYO hydrogels to repair myocardial infarction in rats. This hydrogel recruited endogenous cardiomyocytes and improved cardiac contractions. Although decellularized matrix hydrogels from different tissues display some repairing effects in myocardial injury, whether and how exactly their material source affects their repair effectiveness remains unclear. It is likely there is a correlation based on previous research showing that extracellular matrix materials have tissue specificity. Decellularized matrix hydrogels derived from peripheral nerves (DNM-G) can promote myelination of axons [14] but are not conducive to synapse formation. Meanwhile, hydrogels derived from spinal cord decellularized matrix facilitate the survival, proliferation, and migration of neural stem/progenitor cells (NSPCs), and promote NSFCs neuronal differentiation [15]; nucleus pulposus decellularized matrix hydrogels derived from intervertebral discs are beneficial to the differentiation of mesenchymal stem cells (MSCs) into nucleus pulposus-like cells; and decellularized matrix hydrogels from annulus fibrosus facilitate the differentiation of MSCs into annulus fibrosus-like cells [16]. [PERSON] et al.