Fibroblast growth factor 21 (FGF21) plays important roles in the regulation of glucose and lipid metabolism and energy balance in mammals. In this study, the full-length cDNA of swamp eel fgf21 was cloned. Sequence analysis showed that swamp eel FGF21 displayed high similarity with FGF21 of other vertebrates. Subsequently, a prokaryotic expression vector for swamp eel fgf21 was constructed, and recombinant FGF21 (rFGF21) was successfully induced and purified. To investigate the potential roles of swamp eel FGF21 in glucose and lipid metabolism, we examined the effects of rFGF21 on regulation of glucose and lipid homeostasis in type 1 diabetes mellitus (T1DM) mice as well as swamp eels under glucose stress. In T1DM mice, the levels of blood glucose, serum triglyceride (TG), liver TG, serum total cholesterol (TC), and liver TC were significantly downregulated after repeated daily injection of rFGF21 for 15 days. In addition, liver pathological section analysis indicated that rFGF21 alleviated the degree of damage to liver cells in T1DM mice. Furthermore, rFGF21 significantly upregulated the mRNA expression levels of peroxisome proliferators-activated receptor alpha (Pparα), β-Klotho, fibroblast growth factor receptor 1 (Fgfr1), phosphoenolpyruvate carboxykinase (Pepck), glucose transporter 1 (Glut1), and glucose transporter 4 (Glut4) in T1DM mouse livers. Moreover, in swamp eels, rFGF21 significantly decreased blood glucose and liver TC levels under glucose stress and upregulated the mRNA expression levels of fgf21, pparα, β-klotho, and fgfr1 in liver tissue. These results suggested that FGF21 plays important roles in the regulation of glucose and lipid homeostasis in swamp eel.

成纤维细胞生长因子 21 (FGF21) 在调节哺乳动物的糖脂代谢和能量平衡方面发挥着重要作用。本研究克隆了沼泽鳗fgf21的全长cDNA 。序列分析表明，沼泽鳗鱼FGF21与其他脊椎动物的FGF21具有高度相似性。随后，沼泽鳗鱼fgf21的原核表达载体构建并成功诱导纯化重组FGF21（rFGF21）。为了研究沼泽鳗鱼 FGF21 在葡萄糖和脂质代谢中的潜在作用，我们检查了 rFGF21 对 1 型糖尿病 (T1DM) 小鼠以及葡萄糖应激下沼泽鳗鱼的葡萄糖和脂质稳态调节的影响。在 T1DM 小鼠中，每天重复注射 rFGF21 15 天后，血糖、血清甘油三酯 (TG)、肝 TG、血清总胆固醇 (TC) 和肝 TC 水平显着下调。此外，肝脏病理切片分析表明，rFGF21减轻了T1DM小鼠肝细胞的损伤程度。此外，rFGF21 显着上调过氧化物酶体增殖物激活受体α ( Pparα )的 mRNA 表达水平，T1DM 小鼠肝脏中的 β-Klotho、成纤维细胞生长因子受体 1 ( Fgfr1 )、磷酸烯醇丙酮酸羧激酶 ( Pepck )、葡萄糖转运蛋白 1 ( Glut1 ) 和葡萄糖转运蛋白 4 ( Glut4 )。此外，在沼泽鳗鱼中，rFGF21 显着降低葡萄糖应激下的血糖和肝脏 TC 水平，并上调肝组织中fgf21、pparα、β-klotho和fgfr1的 mRNA 表达水平。这些结果表明FGF21在调节沼泽鳗的葡萄糖和脂质稳态中起重要作用。