Ultrastructural changes in dermal pig skin after exposure to heat and electric energy and acid and basic solutions

In order to describe the ultrastructure of the histopathological changes in dermis after exposure to electrical energy, heat energy and acid and basic solutions the skin of fully anaesthetized Danish Landrace pigs were exposed to direct current, heat (80 degrees C and 450 degrees C) and acid and basic solutions. Biopsies were obtained immediately after the exposure from all types of injury. Biopsies from the cathode areas biopsies were also taken on day 1 and day 2.5 in order to describe the initial calcium deposits. Homogeneous collagen fibres without any birefringence from heat exposed areas were ultrastructurally composed of filamentous materials. Collagen fibres with fine densely spaced cross-striation from cathode areas and areas exposed to basic solutions were shown ultrastructurally to consist of parallelly arranged collagen fibrils with regular waves. It is concluded that the cross-striation of the collagen fibres observed in polarized light are due to a periodic change in the orientation of the fibres seen as waves of the fibres. The ultrastructure of dermal cells were similar to that of epidermal cells following the different types of influence. Characteristically the nuclei were condensed following heat and more electron-lucent following direct current (d.c.) and acid and basic solutions. In cathode areas and areas influenced by basic solutions the electron-lucent nuclei contained fine fibrils. The ultrastructural study supports the suggestion from light microscopic studies that the morphology of anode and cathode lesions shows resemblance to acid induced and basic induced lesions, respectively. Apatite crystals were observed on day 2.5 at the periphery of the collagen fibrils and in the matrix of elastic fibres.