Structural And Biomechanical Properties Of Accelular Dermal Matrix Derived From Human Scar Tissue

Objective To detect the structural and biomechanical properties of the acellular dermal matrix(ADM) of human scar tissue.Methods Randomly choose 8 human mature scar tissue,8 human hypertrophic scar tissue, and 4 normal human tissue as experimental samples, respectively. Then, 0.5mm split-thickness skin grafts were obtained by drum-type scalpel, further acellularized by 2.5g/L trypsin-0.5% Triton X-100 to gain ADM. Structural analysis were carried out by macroscopic observation, HE histological staining, and scanning electron microscope methods. Then, human epithelial cells were inoculated, cultured on those materials, and to observe their adhesive properties. Finally, biomechanical properties of those ADM were analyzed through the detection of stress-strain relation, stress relaxation, creep and ultimate stress strength to study the distinctions of different origin.Results Prepared ADM were milky white in color despite their distinct origins, physiological and mature scar tissue derived ADM were soft and flexible in texture, while ADM from hypertrophic scar group showed a more tenacious character. Optical microscopic and electron microscopic analysis showed no sign of visible cellular structures. ADM from physiological group were characterized with a relatively homogeneous and inerratic collagenous fibers, ADM from hypertrophic group presented with fibers of various diameters and arranged in a compact and disordered manner. ADM from mature scar tissue possessed a trait between the other two groups. Adhesion growth can be observed two weeks after inoculating human epithelial cells on ADM, and cells growth in a gathered fashion on ADM both from normal skin and mature scar tissue, and in an adhesive fashion on hypertrophic scar tissue ADM. Stress-strain β value(3.024±0.413, 2.595±0.443, 2.590±0.366), creep slope(0.018±0.003, 0.019±0.009, 0.023±0.010) and ultimate stress strength(8.971±2.434, 11.011±1.492, 15.567±2.931) of ADM show no significant differences in the hypertrophic scar tissue, mature scar tissue and normal skin tissue( all P>0.05). ADM from mature scar and normal skin tissue showed no differences in stress-strain streth ratio(0.238±0.083 vs 0.291±0.048), relaxation slope(-0.041±0.009 vs-0.047±0.008), total relaxation(0.775±0.194 vs 0.968±0.211), total creep(0.033±0.022 vs 0.049±0.020)( all P>0.05). However, the above related index in ADM from hypertrophic scar tissue(0.188±0.036,-0.033±0.006, 0.481±0.058, 0.020±0.005)were significantly lower than those from the normal tissue( all P<0.05).Conclusion There are no significant differences between mature scar tissue and normal skin tissue derived ADM both in structural and biomechanical aspects, yet ADM from mature scar appears to be superior in biomechanical properties than hypertrophic scar derived ADM, which makes it a possible replacement for original dermis in wound repair.