团头鲂GPR43基因克隆、组织分布及黄连素对其mRNA表达量的影响

GENE CLONING OF GPR43 AND ITS DISTRIBUTION IN THE TISSUE OF BLUNT SNOUT BREAM AND THE EFFECT OF BERBERINE ON ITS MRNA EXPRESSION

  • 摘要: 试验采用RACE技术克隆了团头鲂(Megalobrama amblycephala)G蛋白偶联受体43(GPR43)基因的cDNA序列, 并探究了不同组织中的GPR43 mRNA表达量及黄连素对其表达量的影响。结果显示, 克隆得到的团头鲂GPR43基因的cDNA序列全长为2026 bp, 含有1个长度为 981 bp的开放阅读框, 编码了326个氨基酸。RT-PCR检测发现GPR43在团头鲂的肠道、肌肉、鳃和肝胰腺中具有较高的表达。为期8周的养殖试验选取均重为(80.00±0.90) g的团头鲂320尾, 随机分于16个网箱中, 饲喂4种不同的试验日粮, 分别为正常日粮(脂肪含量为5%)、正常日粮+50 mg/kg黄连素、高脂日粮(脂肪含量为10%)、高脂日粮+50 mg/kg黄连素。结果显示: 在肠道组织中, 与正常日粮组相比, 高脂组的GPR43表达量降低, 添加黄连素能够显著升高其表达水平(P<0.05)。与正常日粮组相比, 高脂组的胆固醇(CHO)含量以及细胞分裂素蛋白激酶(p38)的表达量均呈现了显著上升(P<0.05)的趋势, 添加黄连素后其含量及表达量显著下降(P<0.05)。肝胰腺组织和肌肉组织中的多不饱和脂肪酸(PUFA)含量变化也有着相似的趋势, 而肉碱棕榈酰基转移酶Ⅰ(CPT Ⅰ)、过氧化物酶体增值因子α&β (PPARα&β)、AMP依赖性蛋白激酶(AMPK)的表达量以及2个组织中的饱和脂肪酸(SFA)和单不饱和脂肪酸(MUFA)含量呈现出了相反的趋势。此外, 在正常日粮中添加黄连素并不能对上述各指标产生明显的调控效应, 有时反而会导致轻微的负调控效应。综上结果表明, 黄连素能够显著上调GPR43在高脂抑制下的表达量, 同时能够缓解高脂诱导的团头鲂肝胰腺脂肪沉积, 改善其脂肪代谢性能。黄连素对于脂肪代谢的调控作用可能通过GPR43受体来实现。

     

    Abstract: This study was conducted to explore the effects of berberine on the mRNA expression of G protein coupled receptors 43 (GPR43) and the lipid metabolism performance of blunt snout bream fed with high-fat diet. GPR43 in blunt snout bream was cloned and sequenced with a RACE assays. The effects of berberine on GPR43 mRNA expression in tissues were also investigated. The obtained full-length nucleotide sequence covers 2026 bp, which has an open reading frame of 981 bp, and translates a total of 326 amino acids. Moreover, GPR43 mRNAs were detected in different tissues of blunt snout bream. In blunt snout bream, the expression of GPR43 in intestine, hepatopancreas, gill and white muscle were the highest. 320 fish (80.00±0.90) g were randomly divided into four trial groups (each has four replicates) and fed with 4 diets (normal diet, normal diet with 50 mg/kg berberine, high-fat diet, and high-fat diet with 50 mg/kg berberine, among which normal diet has 5% lipid and high-fat diet has 10% lipid), respectively. The expression of GPR43 mRNA in the high-fat diet group decreased compared with control group, while it significantly increased (P<0.05) after adding in berberine. Compared with the control group, the contents of free fatty acids (FFA), triglycerides (TG), cholesterol (CHO), and mRNA expressions of Cytokinins protein kinase (p38), and Peroxidase value-added factor (PPARγ) all increased (P<0.05) in the high-fat group, but a dramatic decrease (P<0.05) happened after adding in berberine. The same result was found on the composition of Polyunsaturated fatty acids (PUFA) in hepatopancreas and muscle tissues. A completely inverse variation was presented on the mRNA expressions of Carnitine palm acyltransferaseⅠ (CPTⅠ), Peroxidase value-added factor (PPARα&β) and AMP dependent protein kinase (AMPK), as well as on the compositions of Saturated fatty acids (SFA) and Monounsaturated fatty acids (MUFA) in both tissues. Nevertheless, the difference between berberine supplemental normal diet group and control group was out of regular pattern. So further work is still needed to explore the role of berberine in normal circumstances. Overall, the results showed the supplement of berberine could slow down lipid deposition in hepatopancreas, and restore lipid homeostasis which has been damaged by continuous high-fat diet feeding.

     

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