羔羊肝脏IGF-I和IGF-I R基因表达的发育性变化研究

【目的】通过对羔羊IGF-Ⅰ和 IGF-ⅠR基因表达的发育性变化的研究，为羔羊生长发育规律提供理论依据。【方法】选择2、30、60、90和120日龄的雄性哈萨克羊和新疆细毛羊各6只（共54只，120日龄只有新疆细毛羊），测体重后屠宰，采取肝脏，用荧光实时定量PCR法，以GAPDH基因为内标，检测IGF-Ⅰ和IGF-ⅠR基因的发育性变化，并进行品种之间比较。【结果】（1）肝脏IGF-Ⅰ基因的表达量都呈先升后降的趋势，其中雄性哈萨克羊肝脏IGF-Ⅰ基因的表达量从2日龄到60日龄持续上升，60日龄后开始下降，90日龄的表达量显著低于前三个时期（P＜0.05）；雄性新疆细毛羊肝脏IGF-Ⅰ基因的表达量从2日龄到90日龄持续上升，90日龄后开始下降，120日龄的表达量显著低于60日龄（P＜0.05）。雄性哈萨克羊肝脏IGF-Ⅰ基因的表达量在2日龄时与新疆细毛羊差异不显著（P＞0.05），在30～60日龄期间都显著高于新疆细毛羊（P＜0.05），在90日龄时极显著高于新疆细毛羊（P＜0.01）；（2）肝脏IGF-ⅠR基因的表达量都呈现持续下降的趋势，其中哈萨克羊肝脏IGF-ⅠR基因在2日龄的表达量最高，然后就持续下降，2日龄时的表达量与其他各时期差异显著（P＜0.05）；新疆细毛羊肝脏IGF-ⅠR基因在2日龄的表达量最高，然后就持续下降，2日龄时的表达量与其他各时期差异显著（P＜0.05）。哈萨克羊肝脏IGF-ⅠR基因的表达量在2和90日龄时都极显著低于新疆细毛羊（P＜0.01）。【结论】羔羊肝脏组织中IGF-Ⅰ和IGF-ⅠR的基因表达量有特定的发育模式，IGF-ⅠR的基因表达水平的变化不依赖IGF-Ⅰ的基因表达水平。

Studies on The Developmental Patterns of IGF-I and IGF-I R Gene Expression in Liver Tissue of Lamb

Objective Through studying on the developmental patterns of IGF-I,IGF- I R gene expression in the liver tissue of lamb, a theoretic basis of growth and development in lamb was provided. MethodIn the experiment, a real time polymerase chain reaction (PCR) was applied to investigate the development patterns of IGF- I, IGF- I R mRNA expressions in the liver tissue of lamb. GAPDH internal standards were used as control. 54th of XJ fine sheep and Kazakh sheep were sampled at the age of 2,30,60,90,120 days respectively (There were only six XJ fine sheep at the age of 120 days). Result (1) First, the expression levels of IGF- I mRNA in liver tissue increased and declined thereafter gradually. The expression of IGF- I mRNA in Kazakh sheep increased gradually between 2 and 60 days. It declined gradually after 60 days. The expression IGF- I mRNA in XJ fine sheep increased gradually between 2 and 90 days, and it declined gradually after 90 days. The expression of IGF- I mRNA in Kazakh sheep was higher than that in XJ fine sheep at 30 and 60 day (P<0.05), and at 90 days (P<0.01). (2) The expression levels of IGF-I mRNA in liver tissue declined gradually. The expression of IGF-I Mrna in Kazakh sheep was highest at 2 days and declined gradually thereafter. The expression of IGF-IR mRNA in Kazakh sheep at 2 days was higher than that at the other days of age (P<0.05). The expression of IGF-I mRNA in XJ fine sheep was highest at 2 days and declined gradually thereafter. The expression of IGF-I R mRNA in XJ fine sheep at 2 days was higher than that at the other days (P<0.05). The expression of IGF-I R mRNA in Kazakh sheep was lower than that in XJ fine sheep at 2 and 90 days of age (P<0.01). ConclusionThe result show that the IGF-I and IGF-I R mRNA expression in liver tissue follow specific developmental patterns respectively. Level of IGF-IR mRNA expression does not depend on that of IGF-I mRNA expression.