A Porcine Bioassay Method for Analysis of Thermally Protective Fabrics: A Histological and Burn Depth Grading System

摘要

A histopathological and burn depth grading system that can be employed in a porcine bioassay of thermal injury is described. Biopsy specimens taken from burn sites including both burned and normal skin were fixed in unbuffered formalin, embedded in Paraplast, sectioned at 6-7 microns, and stained using a Naval Aerospace Medical Research Laboratory modification of an Armed Forces Insititute of Pathology hematoxylin and eosin method. Completed slides were graded by a pathologist using a scale of from 0 for no thermal damage, to 10 for thermal damage into the subcutaneous fat. Measurements of normal epidermal thickness (A), normal dermal thickness (B), and burned dermal depth (from the epidermal-dermal border down to the damaged/normal tissue border (D-C), were made using standard optical techniques. In order to account for swelling or shrinkage at the burn site, additional measurements including (D) dermal thickness at burn site, (E) total skin thickness at the burn site, and (C) burn depth as measured from the fat/dermal border up to the junction between normal and damaged skin were subsequently made. The method provided the quantitative burn depths required for mathematical model development but is somewhat tedious to be used in screening thermally protective fabrics.