Different Intracapsular Pressure On Different Parts Of The Impact Of Physical And Chemical Properties Of The Goat Skin

Objective: The technique for expanding skin has been applied in clinical medicine for many years, but has not yet been done in veterinary clinic. At present, determination methods on the internal pressure in the expender capsule (called as intracapsular pressure), which may be used in clinic, and the comparative studies on the expanded skins in different locations of the body were rarely reported. With regards to this, the best intracapsular pressure promoting the skin surface-area increase, and the histopathological changes and collagen content in the expended skin were observed in the experiment.Methods: The skin-expander was implanted in the subcutaneous tissue in different locations of the goat (back, head, chest, and leg) by surgery. The sterile normal sodium was regularly injected into the internal capsule at a seven-day internal postoperation, and then the skin-expander pressure, was measured by the biological signal acquisition system during injecting. The histopathological changes and collagen contents in the expended skin were simultaneously studied, and the surface-area of the expanded skin was calculated by the shape model of the skin, which were evaluated the effect of the internal pressure on the skin growth, and on the physical and chemical properties of the expended skin.Results: The intracapsular pressures, in all the above locations, were 0 mmHg at the first injection time. As water injected into the capsule of skin-expender, the intracapsular pressure, with 8~9 mmHg, was one of the highest in the chest, but that, about 0.5 mmHg, in the back location was the lowest at the second injection time. At the third injection time, the intracapsular pressure, about 13 mmHg, was the highest in the head, but in the back it, about 1 mmHg, was the lowest among them. While injecting with water at the fourth time, the intracapsular pressure in the head was much larger than that in other capsules (P<0.05), with 25 mmHg ~ 35 mmHg, and the pressure in the back capsule still was the lowest, with 2 ~ 3 mmHg. The intracapsular pressure in the head decreased rapidly, that in the chest and leg did slightly, but the pressure, with 7 ~ 8 mmHg, increased gradually in the back capsule at the fifth injection time. The best intracapsular pressure in different locations was not in same, it is 0.5mmHg in the back, or 13.4 mmHg in the head, or 8.6 mmHg in the chest, or 2.4 mmHg in the leg, which might promote skin surface-area growing. The growth velocity of the expended skin was rapid in the and head after the 3rd injection time, and also in back ,chest and leg after the 2nd injection time.In control groups, basal layer cells in the skin epidermis appeared splitting phenomenon only at the equivalent time as the 1st injection time in experimental groups, and the granular layer cells became bigger than normal only at the equivalent time as the 3rd or 4th injection time in experimental groups, but did not in the other times. There were not significant changes in the horny layer in control groups.The results of histomorphological observations in experimental groups showed that the basal layer cells in the skin epidermis divided rapidly, the amount of the cells increased, and the cell body became bigger. The space between the prickle cells grew, but the cell body did not changed significantly. At the 3rd injection time there were a number of vacuoles, in different size, among the prickle cells in the chest skin, and then they disappeared. During the previous 3 times the granular layer cells significantly increased in size, but gradually returned to normal size, and the analosis occurred in some of them, and the horny layer cells gently proliferated.The collagen fibers in goat skin dermis became thickening in the initial stage,and the interval distance between the collagen bundles gradually increased, then the the collagen bundles changed from gross fascicular structure to collagen filaments, the collagen fibers orientating from the wave-like to the irregular orientation. The concentrated collagen were glaebule or lamellar, and fibroblasts abundantly proliferated (esp. before the 3rd injection time) and formatted into basophilous cell mass, then proliferated lightly and in disorder among the collagen fibers.In control groups, there were no significant changes in the collagen fibers of dermis, showing the same arrangement in a wave-like, level or same direction. The interval distance between the collagen bundles slightly increased, and the fibroblasts were proliferated on the 14th day after operation, then they retuned to normal condition.There were not the same changes in the collagen content of goat skin in experiment groups at different times. The skin in the back contained much collagen and reached a peak at the 3rd injection time, significant compared to the control groups (P <0.01). The collagen content in head skin were significant increase at the 2nd injection time than that in control groups (P<0.05), then rapidly decreased. The collagen content in the chest changed in "U" curve-like, reached a minimum value at the 2nd and 3rd injection time, but no significant difference (P> 0.05) compared with the control group. The collagen content were significant increased at the 2nd injection time than that in control groups (P <0.05), and reached a peak value.