In vitro effects of ?-carrageenin in the head-kidney leucocytes of gilthead seabream (Sparus aurata)

The lambda-carrageenin is a sulphated mucopolysaccharide that has been used for decades to induce experimental inflammation in mammals. However, it has been little considered in fish. We studied the in vitro effects of lambda-carrageenin on gilthead seabream (Sparus aurata L.) head-kidney leucocytes (HKLs). For this purpose, HKLs were incubated with serial concentrations (from 0 to 1,000 mu g mL(-1)) of lambda-carrageenin for 3, 6, 12 and 24 h to assess its influence on cell viability and morphology, cell activity and modulation of several selected inflammation-related genes. The viability results demonstrated that lambda-carrageenin has no negative effects on HKLs. The respiratory burst activity and phagocytic ability of HKLs after being incubated with lambda-carrageenin (100 and 1,000 mu g mL(-1)) for 24 h were increased, whereas the phagocytic capacity was inhibited by the higher dose at the same experimental time compared with control samples. However, the peroxidase activity of HKLs was not changed by incubation with lambda-carrageenin. According to transmission electron microscopy results, in-cubation of HKLs with the higher dose of lambda-carrageenin appeared to activate the cells being evident different morphological changes without sign of cell death. Furthermore, up-regulation of three proinflammatory cyto-kines (il1b, tnfa, and il6) and down-regulation of anti-inflammatory genes (tgfb) were denoted in HKLs incubated with carrageenin. The present results provide a detailed approach to the effects of lambda-carrageenin on fish leuco-cytes, which could have some impact on how we understand the response of these cells when inducing an in-flammatory process in fish.

Automated summary

This study investigated the effects of lambda-carrageenin on gilthead seabream head-kidney leucocytes (HKLs). The results showed that lambda-carrageenin had no negative effects on cell viability but increased respiratory burst activity and phagocytic ability of HKLs. It also affected the expression of inflammation-related genes.