Potential risks prompted from epicutaneous and intranasal exposure to indoxacarb in rats

Indoxacarb (IDX) is a new highly selective insecticide with excellent activity against a wide variety of pests. This study evaluated the possibility of dermal and nasal mucosal absorption of indoxacarb in rats in order to assess the potential hazards to humans and animals. 28 female albino Wistar rats were randomly divided into 4 groups (n = 7) as follow: group 1 (Ctrl1) normal saline via intranasal route, group 2 (Ctrl2) normal saline via topical dressing, group 3 (IDX-IN) IDX via intranasal route (0.42 mg/L, 1/10 LC50), and group 4 (IDX-T) the same concentration of IDX via topical dressing. The results revealed the highest serum levels of ALT, AST, CPK, and LDH in the IDX-T group, but the lowest level of IgG and IgM were recorded in the IDX-IN group. Furthermore, the IDX-T group exhibited various degrees of histopathological changes in most organs including skin, liver, heart, and lungs, while IDX-IN group showed prominent lesions in the lungs, immune organs, and most brain areas. The histopathological lesions were confirmed by the caspase-3 immunostaining that demonstrated strong casp-3 expression in the lungs, spleen, thymus, and brain of IDX-IN group, whereas IDX-T group noticed higher casp-3 expression in liver, heart, and lungs sections than IDX-IN group.