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[Effects of modified acellularization process on porcine endogenous retroviruses in porcine aorta valves].

OBJECTIVE
to study the effect of modified acellularization process on porcine endogenous retrovirus (PERV) in porcine aorta valves (PAVs).


METHODS
Twenty aortic valves of pig were put into 0.1% trypsin solution, hypotonic and hypertonic TritonX-100, DNAse solution, RNAse solution, and Hanks solution in succession so as to remove the cells. The specimens of PAV were to undergo gross observation and microscopy before and after the acellularization procedure. Fracture test was made. Primers specific for the conservative gag gene of PERV were designed PCR and RT-PCR were used to detect the expression of gag. In addition, 20 samples of native PAV were collected. Peripheral mononuclear cells (PBMCs). Were isolated from 20 samples of porcine peripheral blood. Ten dogs underwent acellularized PAV replacement; 3 months later, samples of the dogs' peripheral blood were collected. Porcine kidney cells of the line PK15 were used as positive controls.


RESULTS
Microscopy showed that all the cells were removed from the acellularized PAVs. Histological analysis showed that the major structural components were maintained. There was no significant difference in fracture strength between the native and acellularized PAVs (P > 0.05). PCR and RT-PCR showed a PERV 219 bp DNA fragment, 90%-95% homologous with the published PERV gene, in the genomic DNA of all native PAVs, pig PBMCs, and PK15 cells, but not in the acellularized PAVs and dog PBMCs.


CONCLUSION
PERV exists in all native PAVs. The modified acellularization process succeeds in removing all the cell component and PERV in the PAVs, thus preventing cross-species transmission of PERV.