Effects of Astragalus polysaccharides (APS) on the expression of immune response genes in head kidney, gill and spleen of the common carp, Cyprinus carpio L

Abstract

For fish immune defences, cytokines and anti-microbial peptides (lysozyme) in circulating system play important roles. In the present study, the effects of Astragalus polysaccharides (APS) injection on gene expression of interleukin 1beta (IL-1beta), tumor necrosis factoralpha (TNF-alpha) and lysozyme-C in the head kidney, gill and spleen of common carp were determined using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). After injection of APS, IL-1beta mRNA level increased in a dose-dependent manner in the head kidney, while no significant changes were found in the gill and spleen. High dose of APS up regulated TNF-alpha transcription in the gill and spleen, while TNF-alpha mRNA level decreased significantly in the head kidney of low dose of APS. Lysozyme-C mRNA levels were up regulated in the gill of low dose of APS and spleen of middle dose of APS. No effect of the APS on lysozyme-C expression was observed in head kidney. These results constitute a first step toward the understanding of APS effect on cytokines and immune-related gene expression in different organs of common carp.