Immunohistochemical and histopathological changes in the skin of rats after maneb application

To determine the immunohistochemical and histopathological changes in facial skin after exposure to maneb (manganese ethylene bisdithiocarbamate), a fungicidal dithiocarbamate pesticide.

In the experimental group maneb was administered by inhalation to 10 male Wistar albino rats for 5 days each week for 3 weeks. As a biological control, the control group (n = 10) received distilled water by spray for the same time period. The experiment was terminated after 3 weeks. Sections of rat facial skin were examined histopathologically.

In the experimental group, microscopic examination of facial skin revealed degeneration of the epidermis, detection of mild inflammatory reaction, and vascular dilation in the connective tissue. Hair follicles and degenerative changes were observed in the deeper parts. In the experimental group, dilation of the blood vessels in the dermis and hemorrhage were supported by an increase in CD34 expression. In addition, a reduction in the number of melanocytes (hypopigmentation) was observed in the hair follicles and epidermis, along with a decrease in the expression of CD117.

Epidermal degeneration, intradermal cell infiltration, vascular changes, and reduction in the number of melanocytes in the follicle and content of cytokeratin in both the epidermis and hair follicle keratinocytes were detected after maneb application. These findings may have important implications in the association with main signaling pathways, including keratinocyte proliferation and differentiation. Disruption of these pathways may cause some dermatoses.