Immunological and histopathological responses of the kidney of common carp (Cyprinus carpio L.) sublethally exposed to glyphosate

• Glyphosate has low toxicity to common carp.
• Glyphosate-exposure altered renal IgM and C3 contents and lysozyme activity.
• Glyphosate-exposure caused renal histopathological damage.
• Glyphosate exerts immunotoxicity on common carp.

Glyphosate is a broad-spectrum herbicide frequently used world widely in agricultural and non-agricultural areas to control unwanted plants. Health risk of chronic and subchronic exposure of glyphosate on animals and humans has received increasing attention in recent years. The aim of this study was to evaluate the effects of glyphosate on the immunoglobulin M (IgM), complement C3 (C3), and lysozyme (LYZ) in the kidney of common carp exposed to 52.08 or 104.15 mg L−1 of glyphosate for 168 h. The results showed that the transcriptions of IgM, C3, or LYZ were altered due to glyphosate-exposure, for example, IgM and C3 initially increased at 24 h later it decreased (except for a increase of C3 in higher dose group at 24 h) while the expression of G-type LYZ were not affected at 24 h, then increased at 72 h, but decreased at the end of test, however C-type LYZ expression was initially up-regulated (24–72 h) but down-regulated at the end of exposure (168 h). However, glyphosate-exposure generally decreased the contents of IgM and C3 or inhibited LYZ activity in the kidney of common carp. In addition, glyphosate-exposure also caused remarkable histopathological damage, mainly including vacuolization of the renal parenchyma and intumescence of the renal tubule in fish kidney. The results of this study indicate that glyphosate causes immunotoxicity on common carp via suppressing the expressions of IgM, C3, and LYZ and also via damaging the fish kidney.