Journal of Clinical Toxicology
Open Access

Abstract

Polycyclic Aromatic Hydrocarbons: Role of Apoptosis in Dermatotoxic and Carcinogenic Effect in Asphalt Road Paving Workers

Ghada Attia Eshak, Morid malak Hanna and Manal Ismael Ahmed

Asphalt contains a complex mixture of polycyclic aromatic hydrocarbons (PAHs). This work aimed firstly to assess the dermatotoxic and carcinogenic risk associated with chronic PAHs exposure, and secondly to investigate the causal relationship between PAHs exposure and cancer through studying the effect of PAHs on apoptosis. This effect was studied by examining the expression pattern of P53, Bax and Bcl-2 apoptotic proteins in skin specimens from road paving workers. The study was conducted on one hundred and fifty two male subjects classified into 122 asphalt fumes exposed workers (tested group) and 30 non exposed workers (control group); careful skin examination and skin biopsies were obtained from all participants after written consent. Biopsies were examined histopathologically and immunohistochemically. SPSS version 15.0 was used for statistical analysis. Results showed that 71 (58.19%) PAHs exposed workers had erythema, itching, excoriations, chronic dermatitis, chemical keratosis, keratoacanthoma (KA) and nine (7.38%) exposed workers had squamous cell carcinoma (SCC). Imunohistochemically, wild type P53 was significantly higher in epidermal keratinocytes of PAHs exposed normal uninvolved (non lesional) skin (t=0.51, P=0.04) and mutant type P53 was significantly higher in SCC cases (t=4.79, p=0.003) when compared with control. A significant increase in Bax expression was observed in all asphalt exposed workers when compared with the control (t=2.73, P=0.03). A significant decrease in Bcl-2 expression was noted in PAHs exposed un-involved skin (t=2.49, P=0.047) while none of the 9 tested SCC cases were positive for Bcl-2. It could be concluded that chronic exposure to PAHs fumes in asphalt workers may increase the risk for developing dermatotoxic and/ or cancer through disturbing apoptosis. Although PAHs exposure can disturb P53, Bax and Bcl-2 apoptotic protein, more extensive researches on other factors involved in controlling apoptosis as Bcl-xl, Caspase family and Fas are to be undertaken.