饥饿和复投喂对虎龙斑生长及LPL、HL基因表达的影响

Effects of Starvation and Re-feeding on the Growth and Expression of LPL and HL Genes in Tiger-Dragon Grouper

为探究饥饿和复投喂对虎龙斑体长、体重的影响及对肝组织脂蛋白酯酶基因LPL及肝脂酶基因HL mRNA表达的影响,为进一步研究饥饿对虎龙斑脂代谢调控机理奠定基础.试验设计0,10,20,30,40 d饥饿区间,饥饿10 d后复投喂10d,每隔10 d取样,测定其体长、体重,并取肝组织,通过异硫氰酸胍—酚法(Trizol法)提取总RNA,经逆转录成c DNA,用内参基因β-actin鉴定c DNA的质量,最后用实时定量PCR分析不同饥饿程度和复投喂对肝脏LPL和HL基因的表达影响.结果发现饥饿对虎龙斑体长的影响较小,对体重的影响较明显;不同饥饿时段对肝脏LPL和HL的mRNA表达均有显著影响,可明显提高肝脏LPL mRNA表达(P <0. 05),而复投喂则会降低肝脏LPL的mRNA表达水平(P <0. 05);饥饿10,20,30 d后虎龙斑肝脏的HL的表达明显上升(P <0. 05),但是饥饿40 d后,HL的表达并没有显著升高,复投喂后HL的表达下降.本研究表明LPL和HL基因都参与了鱼类饥饿时的脂肪代谢活动,当鱼类处于饥饿状态缺乏外部能源供应时,启动肝脏LPL和HL的mRNA表达,以合成大量的脂蛋白酯酶和肝脂酶,用于催化肝组织中脂蛋白分解,为机体氧化供能提供原料.

The effects of starvation and re-feeding on the length and weight of Tiger-Dragon Grouper and that on the expression of lipoprotein esterase gene LPL and hepatic lipase gene HL mRNA in liver tissues were explored,so as to lay a foundation for further study on the mechanism of starvation on lipid metabolism of TigerDragon Grouper. The starvation intervals of 0,10,20,30 and 40 days were designed. After starvation of 10 d,Tiger-Dragon Grouper was re-fed for 10 days,with the body length and body weight measured every 10 days. The total RNA,extracted from liver tissue by Trizol method,was reverse transcribed into cDNA,the quality of which was identified by internal reference gene beta-actin. Real time quantitative PCR was used to analyze the effects of each starvation level and re-feeding on the expression of LPL and HL genes in liver. Starvation exerts little effect on the length of the body,yet with obvious effect on the body weight. Different starvation periods impose significant effect on the expression of LPL and HL mRNA in the liver,and significantly increase the expression of LPL mRNA in the liver（P〈0. 05）,while re-feeding decreases the expression of LPL mRNA in the liver（P〈0. 05）. After 10,20,30 days of starvation,the expression of HL in the liver increased significantly（P〈0. 05）.However,the expression of HL did not increase significantly after 40 days of starvation,and decreased after repeated feeding. Conclusion： Both LPL and HL genes are involved in lipid metabolism during fish starvation.When fish are starving and lack of external energy supply,they activate the expression of LPL and HL mRNA in the liver to synthesize a large number of lipoprotein esterases and hepatic lipases,which are used to catalyze lipoprotein decomposition in liver tissue and provide raw materials for organism oxidation.