Evaluating the effects of vacuum on the microstructure and biocompatibility of bovine decellularized pericardium.

The aim of this study was evaluating the effects of vacuum on microstructure and biocompatibility of bovine decellularized pericardium. So the bovine pericardia were decellularized and then the vacuum was applied for two periods of time; 90 and 180 min. DNA, glucose amino glycan, collagen and elastin content assay, scanning electron microscopy (SEM) examination, hematoxylin and eosin (H&E) and Masson's trichrome stainings performed to evaluate microstructure of tissues. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test, subcutaneous implantation, and tensile test were used to assay biocompatibility and mechanical properties of decellularized tissues. The results showed that applying vacuum reduced residual DNA significantly. Vacuum after 180 min reduced more residual DNA. There were no significant differences in the content of glucose amino glycan (GAG), collagen, and elastin between the vacuumed and control groups. SEM examination was revealed that vacuum for 180 min increased pore size and porosity more than 90 min and control groups. H&E and Masson's trichrome stainings revealed extracellular matrix preservation after decellularization in all groups. Cell viability was increased in vacuumed samples significantly after 72 h in vaccumed samples. H&E staining and tensile test after implantation of tissues were showed less inflammation in the vacuum applied tissues and increased durability. The vacuum increased DNA removal, pore size, porosity, and biocompatibility in vitro and in vivo and durability of bovine decellularized pericardium in vivo. Considering the important role of time, more studies should be performed to optimize time, intensity, and method of application of vacuum in decellularization of different tissues as well as bovine pericardium.