To observe the effects of different magnitudes of pressure and time on the skin of miniature pig , and make a suitable animal model for skin pressure ulcer.

Four miniature pigs, male, 5-6 months old, and 35-40 kg weight.The 5 cm skin incision perpendicular to the long axis of back was made on both sides of spine. A self-made pressure mode was placed beneath the incision after blunt dissection. There were 8 wounds on each miniature pig and a total of 32 wounds which were randomly divided into group 0 kg/12 h, 0 kg/24 h, 5 kg/12 h, 5 kg/24 h, 10 kg/2 h, 10 kg/6 h, 10 kg/12 h, 10 kg/24 h, 15 kg/2 h, 15 kg/6 h, 15 kg/12 h, 15 kg/24 h, 20 kg/2 h, 20 kg/6 h, 20 kg/12 h, 20 kg/24 h, with 2 wounds in each group. The general situation and histological analysis were observed.

Except that skin under pressure was similar to the normal skin tissue and no abnormality was found microscopically in group 0 kg, skin in other groups had varying degrees of damage. Compressed skin appeared red or white color with congestion or erythema, in which the color change was most obvious in group 20 kg. In light microscope, the typical manifestation included collagen fiber breakage or necrosis, fat cell necrosis, congestion or bleeding in blood vessel.

This self-made pressure mode could mimic the clinical and pathological manifestations of pressure ulcer and make miniature pig model of early stage skin pressure ulcers.