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

• Published in: Fish & shellfish immunology 2022-12, Vol.131, p.160-171
• Main Authors: Campos-Sánchez, Jose Carlos, Gonzalez-Silvera, Daniel, Gong, Xu, Broughton, Richard, Guardiola, Francisco A., Betancor, Mónica B., Esteban, María Ángeles
• Format: Article
• Language: English
• Subjects: Adipocytes; Animals; Aquaculture; Carrageenan; Carrageenin; Diet; Fatty acids; Fatty Acids - analysis; Gilthead seabream (Sparus aurata); Inflammation - chemically induced; Inflammation - veterinary; Sea Bream - physiology; Skin inflammation; Subcutaneous Fat - chemistry
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2022.09.066

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 λ-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 λ-carrageenin compared to fish in the control group. Furthermore, the frequency of adipocytes between 4500 and 5000 μm2 was increased at 6 h in the λ-carrageenin group compared to the control group. Analysis of lipid classes found that fish injected with λ-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 polyunsaturated 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 λ-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 λ-carrageenin in gilthead seabream skin. •An injection of carrageenin increased the area of adipocytes in gilthead seabream skin samples.•FFA content increased at 3 h after carrageenan injection into the fish skin.•Carrageenin injection increased the content of sphingomyelin at 6 h.•SFA, 5-HETE and n-6 PUFA increased at 6 h after carrageenin injection.•MUFA, n-3 PUFA and minor fatty acids decreased at 6 h after carrageenin injection.