Inducible nitric oxide synthase (inos) enzyme activity and transcription level as well as ultrastructural changes in different tissues of grass carp in response to ichthyophthirius multifiliis

Abstract

This study aims to contribute to this growing area of research by exploring the gene expression and enzyme activity of iNOS, and provide new insights into the ultrastructural changes in the kidneys, spleen, skin and gills infected with Ichthyophthirius on grass carp. Furthermore, electron microscopy (EM) findings illustrated the uneven distribution of the macrophages and lymphocytes, and the concentrated and fragmented and/or disappeared cell nuclei in the kidneys, spleen, gills and skin. The extreme ultrastructural changes resulted in the reduction in the number of immune cells and subsequent downregulation of iNOS enzyme activity, especially in the gills and skin of Ichthyophthirius-infected grass carp. Our results showed that enzyme activity and gene expression of iNOS were significantly down-regulated in the kidneys and spleen (P>0.05), gills and skin (P<0.05) compared with the negative control group. The data showed the different levels of damages against I. multifiliis infection in the kidneys, spleen, gills and skin. Taken together, expression and activity of inducible nitric oxide synthase could serve as an important indicator to determine the pathological status of the I. multifiliis-grass carp.

Keywords

• ichthyophthirius multifiliis
• gene expression
• enzyme activity ctenopharyngodon idella inos
• ultrastructural changes