Objective　To compare the dermal tissue structure

content of difference types of collagen and biomechanical properties between Bama miniature pig and human skin

and to identify the histomorphologic reasons that limit the clinical application of porcine acellular dermal matrix. 　Methods　The dorsal fullthickness skin samples were collected from Bama miniature pig and human

and then observed grossly. The sections of these samples were stained by hematoxylin and eosin (HE) staining

Masson’s trichrome staining

sirius red staining and Verhoeff’s Van Gieson (VVG) staining

and were examined under light microscopy. These samples were also observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM）. The relevant data of histological images were measured with image analysis software. In the meantime

these samples were detected by material testing machine for biomechanical properties. 　Results　Compared with human dermis

Bama miniature pig had much thicker dermal collagen bundles [(39.29±10.17)μm vs (17.21±5.20)μm

P=0.000 3]

and had significant decrease in the gap rate between these bundles [(19.01±1.55]%  vs (32.36±1.28)%

P=0.029]. The dermal collagen bundles of Bama miniature pig were densely arranged and had smaller pores by SEM

the collagenous fibrils were thicker

and had longer cyclical transverse striation by TEM. The distribution of elastic fiber

the contents of type Ⅰ and Ⅲ collagen and their ratio also had significant differences between human and porcine dermis (P0.05). The maximum strain of Bama miniature pig dermis (0.52±0.05)mm/mm was smaller than that of human dermis [(0.80±0.06)mm/mm

P=0.003]

while the elastic modulus (69.65±12.16)MPa and maximum stress (20.72±1.49)MPa of Bama miniature pig dermis were stronger than that of human dermis (44.23±4.63) and (11.85±0.19)MPa (P=0.028

P=0.001). 　Conclusion　The dermis of pig and human are quite different. It is suggested that the acelluar dermal matrix from pig is not an optimal biomaterial for repairing and regenerating the human dermis. 