Histological and immunohistochemical study on the effect of passive smoking on the skin of adult male albino rats and the possible protective role of nigella sativa oil

Introduction:Smoking is associated with many dermatological conditions, including poor wound healing and premature skin aging. Nigella sativa, commonly known as black seed or black cumin, is used in folk herbal medicine all over the world for the treatment and prevention of a number of diseases. Aim:The aim of the work is to investigate the effect of smoking on the histological structure of the skin and to evaluate the possible protective role of the nigella sativa oil (NSO). Materials and methods:Twenty adult male albino rats were divided into four equal groups: group I (the control group) was placed 10min twice daily for 4 weeks in a chamber without cigarette smoke exposure and was given a single dose of saline, 10ml/kg BW (body weight) orally and daily, group II (the NSO group) was given a single dose of NSO, 10ml/kg BW orally and daily, group III (the passive smoking group) was exposed to both side stream and main stream smoke for 10min twice daily for 4 weeks, and group IV (the protected group) was exposed to both side stream and main stream smoke for 10min twice daily for 4 weeks simultaneously with a single dose of NSO, 10ml/kg BW orally and daily. Results:Exposure of male albino rats to cigarette smoke for 4 weeks produced some histological changes in the skin in the form of a significant decrease in the thickness of the epidermis and flattening of the epidermal–dermal junction. There was also a significant decrease in the collagen fibers in the dermis and an apparent decrease in the cytokeratin intermediate filaments in the keratinocytes, whereas the histological structure of the skin in the animals that received black seeds oil concomitant with smoke exposure (group IV) was almost similar to that of the control. Conclusion:It was concluded that exposure to cigarette smoke produced some histological changes in the skin similar to that occurring in old age, and administration of black seed oil could protect against these changes in adult male albino rats.