The herbicide atrazine increases mucopolysaccharides and decreases the thickness of the epithelium of the frog Lithobates spectabilis (Ranidae)

The application of herbicides is one of the leading causes of the dedine of amphibians in the world. Atrazine is widely used to control herbaceous weeds in crops. In Mexico, it is not regulated and widely applied. More information regarding the effects of atrazine in aquatic systems and on amphibians in this country is therefore needed. Amphibians have a smooth skin coated with excretions that protect them from harmful environmental influences, yet still facilitates the exchange of gases, ions, and thermoregulation, but is especially susceptible to absorbing toxic substances, induding atrazine. A few studies have revealed that atrazine modifies the thickness of the epithelial layer in fish, but there are few studies to that effect in frogs. No studies have investigated whether atrazine exposure affects mucopolysaccharides or glucans, which are essential for hydrating the skin. We hypothesized and found confirmed that the herbicide atrazine reduces the thickness of the dorsal epithelium and promotes a greater presence of mucopolysaccharides in the dorsal epithelium and glands in Lithobates spectabilis. Our findings suggest that this frog is likely more vulnerable to dehydration, ultraviolet radiation, and will suffer impaired wound healing when exposed to atrazine.