## Results and Discussion
### Proteomic Analysis of pDMYO and pDSIS  
Proteomic analysis showed that pDMYO and pDSIS contained 944 and 161 different proteins, respectively, of which 154 were shared between the two matrices (Figure 4A,B). According to the protein categories, including ECM glycoproteins, ECM accessory proteins, ECM regulatory factors, proteoglycans, and secretory factors, all the protein contents of pDMYO were higher than those of pDSIS (Figure 4B). Figure 4C,D show the types of matrix histones and proportion of different proteins in pDMYO and pDSIS. The core matrisome proteins of pDMYO were dominantly ECM glycoproteins (49.6%), followed by collagen proteins (25.4%), whereas pDSIS was mainly composed of collagen proteins (72.1%), followed by ECM glycoproteins (15.2%) (Figure 4C,D). Furthermore, the secretory factors (1.37%) and ECM affiliated proteins (1.77%) were higher in pDMYO. Figure 2: Assessment of the biocompatibility and capacity to sustain cell viability of the porcine decellularized matrix gels and collagen gels on myocardial-related cells. (**A**) Live/Dead staining of cardiomyocytes cultured on three different hydrogels after three days; scale bar = 500 μm; (**B**) Survival rate of cardiomyocytes cultured on three different hydrogels; (**C**) Live/Dead staining of human umbilical vein endothelial cells cultures on three different hydrogels; scale bar = 500 μm; (**D**) Survival rate of human umbilical vein endothelial cells on three different hydrogels; (**E**) Effect of three different hydrogels on cardiomyocytes viability; (**F**) Effect of three different hydrogels on human umbilical vein endothelial cell viability. * denotes statistical difference within the same group with \(p<0.05\), respectively (\(n>3\)). Figure 4: Proteomic analysis of pDMYO- and pDSIS-gels (**A**) Venn diagram of total proteins in pDMYO- and pDSIS-gels. (**B**) The common and unique matrisome proteins in pDMYO- and pDSIS-gels. (**C**) Types and proportion of matrisome proteins in pDMYO-gel. (**D**) Types and proportion of matrisome proteins in pDSIS-gel. (**E**) Top 10 matrisome proteins in pDMYO-gel. (**F**) Top 10 matrisome proteins in pDSIS-gel. Figure 3: Effects of decellularized matrix and collagen hydrogel on cardiomyocytes morphology and function. (**A**) Video capture of beating cardiomyocytes after seven days in culture on different hydrogels; scale bar = 100 \(\upmu\)m; (**B**) Effect of decellularized matrix and collagen hydrogels on cardiomyocytes occ heating rate; (**C**) Immunofluorescence staining of cardiomyocytes for cTn1 (green) and Cx43 (red), scale bar = 500 \(\upmu\)m; (**D**) Statistical analysis of cTn1 expression. * denotes statistical difference within the same group with \(p<\) 0.05, respectively (\(n>\) 3). In addition, the top 10 proteins in pDMYO-gel were the glycoprotein HSPG2, laminins (LAMB2, LAMC1, LAMB1, FBN1, LAMA2), fibronectin (FN1), and collagen 6 (COL6A2, COL6A3) whereas the top ten proteins in pDSIS-gels were mostly collagen proteins, including COL6A3, COL1A1, COL6A2, COL6A1, COL1A2, FBN1, SERPINC1, COL5A2, HSPG2, and COL5A1 (Figure 4E,F). The relative gene expressions of matrismore proteins were shown in Figures S1 and S2. These results were consistent with the results in Figure 1, showing a higher collagen content in pDSIS than in pDMYO, whereas pDMYO contained more proteins of diverse molecular weights. Figure S3 showed the relative abundance of proteins in pDMYO and pDSIS. Most common proteins expressed highly in both pDMYO and pDSIS belonged to collagen family, ECM glycoproteins, and proteoglycans, including COL1A2, COL6A2, COL1A1, COL4A2, COL6A1, DPT, FN1, and HSPG2. It has been reported that skin bridging protein (DPT) [22], fibronectin (FN1) [23], and heparan sulfate proteoglycan (HSPG2) [24] can promote cell migration, adhesion, proliferation, and tissue repair. Therefore, we proposed that the presence of these proteins may participate in facilitating survival and viability of cardiomyocytes and endothelial cells.