A histological study on the mechanism of epidermal nuclear elongation in electrical and burn injuries

Abstract

Epidermal nuclear elongation is one of the most important signs for the diagnosis of electrical injury. In this study, we investigated the mechanism responsible for this phenomenon by comparing the findings from burn injuries and those from contusions. Electrical and burn injuries were made in the dorsal skin of rats using energy ranging from 100 to 790 joules for electrical injury, and 170-690 joules for burn injury. Contusions were also made by compressing the skin with a vice. In electrical and burn injuries, the dermis under the epidermal elongated nuclei was homogeneous and without empty spaces between collagen bundles and the number of dermal fibroblasts per 0.01 mm2 below the damaged epidermis decreased significantly (P < 0.05). The incidence of this change correlated with the depth of denatured dermal collagen fibres and in both types of injuries, dermal cells had no nuclear antigenicity for ubiquitin. The width of the injured epidermis with nuclear elongation decreased significantly (P < 0.05) and the elongated nuclei were parallel to the basal membrane. In electrical injury however, nuclear elongation occurred more frequently near the external root sheath. Nuclear elongation of fibroblasts and external root sheath cells was also found, but those of sebaceous gland cells were not detected. Epidermal elongated nuclei were also found in contusions. The evidence strongly suggests that epidermal nuclear elongation in electrical and burn injuries is due to dermal expansion by heat.

Heat-induced immunoreactivity of tau protein in neocortical neurons of fire fatalities

“…Standard immunohistochemical methods do not assist in the visualization of normal tau protein in neurons of formalin-fixed brain sections [17,18,19]. Heat is known to denature protein and may change the immunoreaction [20]. Therefore, positive tau immunostaining of neurons in fire fatalities indicates that heat induces a conformational change of tau protein resulting in increased immunoreactivity.…”

Cardiac pathology in death from electrocution

“…The final picture is determined by the type, voltage and intensity of the current [1]. Except for cutaneous electrical and heat-related effects, the other direct effects of electricity essentially leave no trace [2][3][4][5]. The principal cause of death is usually said to be a disturbance in cardiac electric conduction leading to ventricular fibrillation.…”

Histopathological differentiation of skin lesions caused by electrocution, flame burns and abrasion

“…Takamiya et al [5], in their study on electrical and thermal skin lesions and contusions in rats, found that epidermal cells had nuclear elongation in almost all thermal skin lesions, which was correlated with epidermal thinning. It was agreed that epidermal nuclear elongation was an indication of increased heat and that the dermis, which became oedematous due to heat, compressed the epidermis, which in turn flattened the nuclei [5,8]. In the present study, we graded nuclear elongation and found the degree of nuclear elongation to be significantly higher in electrocution ( p = 0.000).…”

“…Formerly, it was maintained that electromagnetic effects of electricity caused pyknotic and elongated nuclei which were arranged in the direction of electric currents [5,6]. However, at present, it is debatable that nuclear elongation can be used to determine electric shock since it has been shown that similar nuclear elongations may occur in thermal burns, blunt traumatic skin injuries, cauterization, drying, and freezing, and around blisters due to barbiturate poisoning [7].…”

“…However, at present, it is debatable that nuclear elongation can be used to determine electric shock since it has been shown that similar nuclear elongations may occur in thermal burns, blunt traumatic skin injuries, cauterization, drying, and freezing, and around blisters due to barbiturate poisoning [7]. Takamiya et al [5], in their study on electrical and thermal skin lesions and contusions in rats, found that epidermal cells had nuclear elongation in almost all thermal skin lesions, which was correlated with epidermal thinning. It was agreed that epidermal nuclear elongation was an indication of increased heat and that the dermis, which became oedematous due to heat, compressed the epidermis, which in turn flattened the nuclei [5,8].…”