Implication of adipocytes from subcutaneous adipose tissue and fatty acids in skin inflammation caused by λ-carrageenin in gilthead seabream (Sparus aurata)

The role of subcutaneous adipose tissue adipocytes and the effects of fatty acids on carrageenan-induced skin inflammation in gilthead seabream (Sparus aurata) were studied. Fish were injected intramuscularly with phosphate-buffered saline (control) or lambda-carrageenin (1%), and skin samples collected at the injection site at 3 and 6 h post-injection (p.i.) were processed for histological study. In addition, the presence and levels of lipid classes, fatty acid methyl esters (FAME) and eicosanoids were evaluated in the skin samples obtained from the injected areas. Histological results indicated an increase in adipocyte area in fish sampled at 3 h p.i. with lambda-carrageenin compared to fish in the control group. Furthermore, the frequency of adipocytes between 4500 and 5000 mu m2 was increased at 6 h in the lambda-carrageenin group compared to the control group. Analysis of lipid classes found that fish injected with lambda-carrageenan showed increased free fatty acid (FFA) and sphingomyelin content at 3 and 6 h, respectively, compared to the control group. An increase in saturated fatty acids (SFA), n-6 poly-unsaturated fatty acids (PUFA), and a decrease in the values of monounsaturated fatty acids (MUFA), n-3 PUFA and minor fatty acids were observed in fish skin at 6 h after lambda-carrageenin injection, with respect to the values obtained in the control group. Regarding the analysis of eicosanoids, an increase in hydroxyeicosatetraenoic acid (5-HETE) was detected in the skin of fish at 6 h post-carrageenin injection compared to the control group. The presented results indicate the contribution of adipocytes and fatty acids in the development and regulation of the inflammatory response triggered by lambda-carrageenin in gilthead seabream skin.

Automated summary

The role of adipocytes and fatty acids in carrageenan-induced skin inflammation was studied in gilthead seabream. Results showed that injection of lambda-carrageenin led to an increase in adipocyte area at 3 hours post-injection and an increase in adipocyte frequency at 6 hours post-injection. Analysis of lipid classes revealed increased levels of free fatty acids and sphingomyelin in the injected fish compared to the control group. The fatty acid profile of the fish skin also showed changes, with an increase in saturated fatty acids and n-6 polyunsaturated fatty acids, and a decrease in monounsaturated fatty acids, n-3 polyunsaturated fatty acids, and minor fatty acids at 6 hours after injection. Evaluation of eicosanoids indicated an increase in hydroxyeicosatetraenoic acid in the injected fish compared to the control group. These findings demonstrate the contribution of adipocytes and fatty acids to the inflammatory response in gilthead seabream skin.