Chemical modification of bovine tissues by dye-mediated photooxidation

Photooxidation of pericardium has been shown chemically to alter and stabilize tissue. The characterization of photooxidatively induced, chemical modifications of bovine pericardial and arterial tissue is reported here.

Tissues were prepared by various methods of photooxidation and analyzed for thermal denaturation temperature, protein extraction, amino acid content and crosslink content.

Photooxidation of tissue resulted in no significant time-dependent changes in thermal denaturation temperature, but did result in a time-dependent alteration and reduction in extracted proteins. This reduction is consistent with chemical alteration and stabilization of the tissue. Photooxidation also resulted in a time-dependent reduction of histidine content in treated tissues by histidine being converted to a non-detectable form. No other amino acid alteration was detected by amino acid analysis. Crosslink analysis of tissue hydrolyzates showed a time-dependent alteration in crosslink content of photooxidized tissue and an apparent addition of several types of new crosslinks.

These chemical modifications are consistent with oxidative modification of amino acids in the tissues, resulting in an alteration of existing crosslinks and possible addition of new crosslinks in the tissues. This treatment process leads to in vivo and in vitro stability of pericardial and arterial tissues with potential use as bioprosthetic materials.