Immunohistochemical detection of fibronectin in postmortem incised wounds of porcine skin.

Fibronectin plays an important role in tissue repair and wound healing. Previous literature reports indicated that fibronectin could be a marker of vitality for wounds with a survival time of more than a few minutes. In order to verify these findings were performed immunohistochemical investigations on the expression of fibronectin in incised wounds of porcine skin inflicted into various anatomical regions in the early postmortem interval (0-5 min after circulatory arrest). Tissue specimens were collected 12-14 h postmortem and investigated for fibronectin on paraffin sections (alkaline phosphatase and monoclonal anti-alkaline phosphatase procedure). A markedly positive expression of fibronectin (not only next to the wound margin and clearly stronger than in normal undamaged skin) could be demonstrated in eleven out of 36 samples. A moderately positive fibronectin reaction was detectable in seven further specimens. Muscular contraction bands were observed in nine out of 36 specimens. The various reaction patterns of fibronectin cannot be finally explained, but are probably due to a passive transudation of skin tissue by blood components from injured vessels. As a result of these investigations the specificity and validity of fibronectin as a parameter of vitality has to be questioned. Fibronectin immunohistochemistry again reveals that the validity of parameters as vital criteria decreases when their manifestation time is short; postmortem/supravital induction seems to be possible resembling vital reactions in these cases.