胆汁酸经典合成途径的基因调节研究
发布时间：2018-09-01 08:21
【摘要】： 第一部分高胆固醇摄入对胆汁酸经典合成途径中基因调节的影响 [目的]检测短期(2天)和较长期(2周)高胆固醇摄入新西兰白兔血清胆固醇、胆汁酸水平及肝脏胆汁酸经典合成途径限速酶CYP7A1、核受体FXR和LXR的激活状态,揭示短期和较长期高胆固醇摄入对胆汁酸合成的不同影响,探讨核受体不同的激活状态对胆汁酸合成不同的基因调节机制。 [方法]将36只新西兰兔随机分为4组:2天对照组、2天胆固醇组、2周对照组和2周胆固醇组,每组各9只。其中对照组分别喂饲普通兔粮2天及2周,高胆固醇组分别喂饲含2%胆固醇兔粮2天及2周,喂饲结束后测定血清总胆固醇、低密度脂蛋白和胆汁酸水平并测定肝脏CYP7A1活性及CYP7A1 mRNA、FXR的靶基因SHP mRNA、BSEP mRNA和LXR的靶基因ABCA1 mRNA、CETPmRNA。 [结果]2天对照组和2周对照组各项指标无差异(P＞0.05)。高胆固醇组的血清总胆固醇、低密度脂蛋白水平均较对照组升高,且2周高胆固醇组高于2天高胆固醇组(P＜0.05);2天高胆固醇组血清胆汁酸水平与对照组相比无变化(P＞0.05),而2周高胆固醇组血清胆汁酸水平较对照组升高(P＜0.05);2天高胆固醇组肝脏CYP7A1活性及CYP7A1mRNA均较对照组升高(P＜0.05),而2周高胆固醇组肝脏CYP7A1活性及CYP7A1mRNA均较对照组降低(P＜0.05);2天高胆固醇组肝脏SHPmRNA、BSEP mRNA与对照组相比无变化(P＞0.05),而2周高胆固醇组肝脏SHPmRNA、BSEP mRNA均较对照组升高(P＜0.05);高胆固醇组肝脏ABCA1mRNA、CETP mRNA均较对照组升高,且2周高胆固醇组高于2天高胆固醇组(P＜0.05)。 [结论]高胆固醇摄入使血清总胆固醇、低密度脂蛋白水平升高。短期高胆固醇摄入可激活肝脏LXR受体继而使CYP7A1活性增加,胆汁酸合成增加;此时体内胆汁酸水平尚未升高故肝脏FXR受体活性不变。当较长期的高胆固醇摄入后,体内胆汁酸水平升高从而激活FXR受体;尽管LXR仍被进一步激活,但FXR对CYP7A1的抑制作用强于LXR对CYP7A1激活作用,CYP7A1活性下降,胆汁酸合成减少。 第二部分考来烯胺对胆汁酸经典合成途径的基因调节及其降低血清胆固醇的机制 [目的]研究考来烯胺对胆汁酸经典合成途径的基因调节及其降低血清胆固醇的作用机制。 [方法]20只新西兰兔随机分为考来烯胺组和对照组,每组10只。考来烯胺组每天予考来烯胺混悬液20ml灌胃共2周;对照组每天予20ml蒸馏水灌胃共2周。实验结束后抽血测定血清总胆固醇、低密度脂蛋白和胆汁酸水平并测定肝脏CYP7A1活性及CYP7A1 mRNA、SHP mRNA、BSEP mRNA和LDL-R mRNA。 [结果]考来烯胺组血清总胆固醇水平和低密度脂蛋白水平较对照组下降(P＜0.05);考来烯胺组血清胆汁酸水平与对照组差异无统计学意义(P＞0.05);考来烯胺组CYP7A1活性及mRNA较对照组升高(P＜0.05);考来烯胺组SHPmRNA和BSEP mRNA均较对照组下降(P＜0.05);考来烯胺组LDL mRNA较对照组升高(P＜0.05)。 [结论]考来烯胺使回流入肝的胆汁酸减少,FXR失活从而对CYP7A1的抑制减弱,CYP7A1活性增高,胆汁酸经典途径合成增加,弥补经肠道丢失的胆汁酸并消耗了肝内的LDL,肝脏摄取循环LDL增加,使血清LDL下降。 第三部分考来烯胺对高胆固醇摄入新西兰兔胆汁酸-胆固醇代谢的影响 [目的]研究考来烯胺对长期(4周)高胆固醇摄入新西兰兔经典途径胆汁酸合成及胆固醇代谢的影响。 [方法]将30只新西兰兔随机分为对照组、高胆固醇血症模型组和考来烯胺组,每组10只。对照组给予普通兔粮,每天予20ml蒸馏水灌胃4周;模型组给予高胆固醇兔粮,每天予20ml蒸馏水灌胃4周;考来烯胺组给予高胆固醇兔粮,每天予考来烯胺混悬液20ml灌胃4周。4周后抽血测定血清总胆固醇、低密度脂蛋白、胆汁酸水平并测定肝脏HMGCoA还原酶活性、CYP7A1活性及CYP7A1mRNA、SHP mRNA、BSEP mRNA和LDL-R mRNA。 [结果]模型组、考来烯胺组血清总胆固醇及低密度脂蛋白均较对照组上升(P＜0.01);考来烯胺组血清总胆固醇及低密度脂蛋白均较模型组下降(P＜0.01)。模型组、考来烯胺组血清胆汁酸水平较对照组上升(P＜0.01),模型组和考来烯胺组血清胆汁酸水平差异无统计学意义(P＜0.01)。模型组CYP7A1活性及mRNA较对照组降低(P＜0.01);考来烯胺组CYP7A1活性及mRNA组较模型组升高(P＜0.01)。模型组HMGCoA还原酶活性较对照组降低(P＜0.01);考来烯胺组HMGCoA还原酶活性较模型组升高(P＜0.01)但与对照组差异无统计学意义(P＞0.05)。模型组肝脏SHPmRNA和BSEPmRNA均较对照组升高(P＜0.01);考来烯胺组肝脏SHP mRNA和BSEP mRNA均较对照组升高(P＜0.01)且较模型组下降(P＜0.01)。模型组LDL mRNA较对照组下降(P＜0.01);考来烯胺组LDL mRNA较对照组和模型组升高(P＜0.01)。 [结论]长期高胆固醇摄入新西兰兔肝脏FXR被激活,CYP7A1活性及其mRNA、HMGCoA还原酶活性、LDL mRNA下降,血清胆固醇、低密度脂蛋白和胆汁酸升高;同时应用考来烯胺可降低FXR活性,CYP7A1活性及其mRNA、HMGCoA还原酶活性、LDL mRNA升高,从而降低血清胆固醇、低密度脂蛋白而胆汁酸水平不变。
[Abstract]:Part 1 the effect of high cholesterol intake on gene regulation in classical synthesis pathway of bile acids
[Objective] To detect the activation of CYP7A1, FXR and LXR in serum cholesterol, bile acid level and classical bile acid synthesis pathway of New Zealand white rabbits fed with high cholesterol for short (2 days) and longer (2 weeks), reveal the different effects of short-term and long-term high cholesterol intake on bile acid synthesis and explore the different stimulation of nuclear receptors. The regulation of bile acid synthesis by living state is different.
[Methods] Thirty-six New Zealand rabbits were randomly divided into 4 groups: 2-day control group, 2-day cholesterol group, 2-week control group and 2-week cholesterol group, 9 rabbits in each group. The activity of CYP7A1, CYP7A1 mRNA, target gene SHP mRNA of FXR, BSEP mRNA, target gene ABCA1 mRNA of LXR and CETP mRNA were measured.
[Results] There was no significant difference in serum total cholesterol and low density lipoprotein levels between 2-day control group and 2-week control group (P > 0.05). The level of serum bile acid in cholesterol group was higher than that in control group (P < 0.05), the activity of CYP7A1 and the expression of CYP7A1 mRNA in liver of two-day high cholesterol group were higher than that in control group (P < 0.05), while the activity of CYP7A1 and the expression of CYP7A1 mRNA in liver of two-week high cholesterol group were lower than that in control group (P < 0.05). The hepatic SHP mRNA and BSEP mRNA in two-week hypercholesterolemic group were higher than those in control group (P < 0.05), while the hepatic ABCA1 mRNA and CETP mRNA in two-week hypercholesterolemic group were higher than those in two-day hypercholesterolemic group (P < 0.05).
[Conclusion] High cholesterol intake can increase serum total cholesterol and low density lipoprotein levels.Short-term high cholesterol intake can activate liver LXR receptor and then increase CYP7A1 activity and bile acid synthesis.The activity of liver FXR receptor remains unchanged after long-term high cholesterol intake. Although LXR is still further activated, FXR has a stronger inhibitory effect on CYP7A1 than LXR does on CYP7A1. CYP7A1 activity decreases and bile acid synthesis decreases.
Part II Gene regulation of classical bile acid synthesis pathway by colineamine and its mechanism of lowering serum cholesterol
[Objective] To study the gene regulation of classical bile acid biosynthesis pathway by colineamine and its mechanism of lowering serum cholesterol.
[Methods] Twenty New Zealand rabbits were randomly divided into two groups, 10 rabbits in each group. Colineamine group was given colineamine suspension 20 ml daily for 2 weeks while control group was given 20 ml distilled water for 2 weeks. P7A1 mRNA, SHP mRNA, BSEP mRNA and LDL-R mRNA.
[Results] The levels of serum total cholesterol and low density lipoprotein in the colineamine group were lower than those in the control group (P < 0.05); the levels of serum bile acid in the colineamine group were not significantly different from those in the control group (P > 0.05); the activities of CYP7A1 and mRNA in the colineamine group were higher than those in the control group (P < 0.05); the SHP mRNA and BSEP mRNA in the colineamine group were higher than those in the control group (P < 0.05). Decrease (P < 0.05); LDL mRNA in the test group was higher than that in the control group (P < 0.05).
[Conclusion] Colineamine decreases bile acid reflux into the liver, inactivates FXR and thus reduces the inhibition of CYP7A1, increases the activity of CYP7A1, enhances the synthesis of bile acid via classical pathway, compensates for the loss of bile acid through the intestine and consumes LDL in the liver, increases LDL uptake by the liver, and decreases serum LDL.
The third part is the effect of enolamine on bile acid cholesterol metabolism in New Zealand rabbits with high cholesterol intake.
[Objective] To study the effects of colineamine on bile acid synthesis and cholesterol metabolism in New Zealand rabbits fed with high cholesterol for 4 weeks.
[Methods] Thirty New Zealand rabbits were randomly divided into control group, hypercholesterolemia model group and colineamine group with 10 rabbits in each group. Serum total cholesterol, low density lipoprotein (LDL), bile acid (bile acid) levels were measured and liver HMGCoA reductase activity, CYP7A1 activity, CYP7A1 mRNA, SHP mRNA, BSEP mRNA and LDL-R mRNA were measured after the suspension was given 20 ml for 4 weeks.
[Results] The serum total cholesterol and low density lipoprotein in the model group were higher than those in the control group (P < 0.01), while the serum total cholesterol and low density lipoprotein in the model group were lower than those in the model group (P < 0.01). There was no significant difference in bile acid level (P < 0.01). CYP7A1 activity and mRNA in model group were lower than those in control group (P < 0.01); CYP7A1 activity and mRNA in colineamine group were higher than those in model group (P < 0.01). HMGCoA reductase activity in model group was lower than that in control group (P < 0.01); HMGCoA reductase activity in colineamine group was higher than that in model group (P < 0.01). There was no significant difference between the model group and the control group (P > 0.05). The hepatic SHP mRNA and BSEP mRNA in the model group were higher than those in the control group (P < 0.01); the hepatic SHP mRNA and BSEP mRNA in the colineamine group were higher than those in the control group (P < 0.01) and lower than those in the model group (P < 0.01). And the model group increased (P < 0.01).
[Conclusion] Liver FXR activity, CYP7A1 activity and its mRNA, HMGCoA reductase activity, LDL mRNA decreased, serum cholesterol, LDL protein and bile acid increased in New Zealand rabbits fed with high cholesterol for a long time, while the activity of FXR, CYP7A1 activity and its mRNA, HMGCoA reductase activity, LDL mRNA increased, and serum cholesterol, LDL mRNA decreased with the application of colineamine. Cholesterol, low density lipoprotein and bile acid level remained unchanged.
【学位授予单位】：复旦大学
【学位级别】：博士
【学位授予年份】：2008
【分类号】：R341
本文编号：2216630
[Abstract]:Part 1 the effect of high cholesterol intake on gene regulation in classical synthesis pathway of bile acids
[Objective] To detect the activation of CYP7A1, FXR and LXR in serum cholesterol, bile acid level and classical bile acid synthesis pathway of New Zealand white rabbits fed with high cholesterol for short (2 days) and longer (2 weeks), reveal the different effects of short-term and long-term high cholesterol intake on bile acid synthesis and explore the different stimulation of nuclear receptors. The regulation of bile acid synthesis by living state is different.
[Methods] Thirty-six New Zealand rabbits were randomly divided into 4 groups: 2-day control group, 2-day cholesterol group, 2-week control group and 2-week cholesterol group, 9 rabbits in each group. The activity of CYP7A1, CYP7A1 mRNA, target gene SHP mRNA of FXR, BSEP mRNA, target gene ABCA1 mRNA of LXR and CETP mRNA were measured.
[Results] There was no significant difference in serum total cholesterol and low density lipoprotein levels between 2-day control group and 2-week control group (P > 0.05). The level of serum bile acid in cholesterol group was higher than that in control group (P < 0.05), the activity of CYP7A1 and the expression of CYP7A1 mRNA in liver of two-day high cholesterol group were higher than that in control group (P < 0.05), while the activity of CYP7A1 and the expression of CYP7A1 mRNA in liver of two-week high cholesterol group were lower than that in control group (P < 0.05). The hepatic SHP mRNA and BSEP mRNA in two-week hypercholesterolemic group were higher than those in control group (P < 0.05), while the hepatic ABCA1 mRNA and CETP mRNA in two-week hypercholesterolemic group were higher than those in two-day hypercholesterolemic group (P < 0.05).
[Conclusion] High cholesterol intake can increase serum total cholesterol and low density lipoprotein levels.Short-term high cholesterol intake can activate liver LXR receptor and then increase CYP7A1 activity and bile acid synthesis.The activity of liver FXR receptor remains unchanged after long-term high cholesterol intake. Although LXR is still further activated, FXR has a stronger inhibitory effect on CYP7A1 than LXR does on CYP7A1. CYP7A1 activity decreases and bile acid synthesis decreases.
Part II Gene regulation of classical bile acid synthesis pathway by colineamine and its mechanism of lowering serum cholesterol
[Objective] To study the gene regulation of classical bile acid biosynthesis pathway by colineamine and its mechanism of lowering serum cholesterol.
[Methods] Twenty New Zealand rabbits were randomly divided into two groups, 10 rabbits in each group. Colineamine group was given colineamine suspension 20 ml daily for 2 weeks while control group was given 20 ml distilled water for 2 weeks. P7A1 mRNA, SHP mRNA, BSEP mRNA and LDL-R mRNA.
[Results] The levels of serum total cholesterol and low density lipoprotein in the colineamine group were lower than those in the control group (P < 0.05); the levels of serum bile acid in the colineamine group were not significantly different from those in the control group (P > 0.05); the activities of CYP7A1 and mRNA in the colineamine group were higher than those in the control group (P < 0.05); the SHP mRNA and BSEP mRNA in the colineamine group were higher than those in the control group (P < 0.05). Decrease (P < 0.05); LDL mRNA in the test group was higher than that in the control group (P < 0.05).
[Conclusion] Colineamine decreases bile acid reflux into the liver, inactivates FXR and thus reduces the inhibition of CYP7A1, increases the activity of CYP7A1, enhances the synthesis of bile acid via classical pathway, compensates for the loss of bile acid through the intestine and consumes LDL in the liver, increases LDL uptake by the liver, and decreases serum LDL.
The third part is the effect of enolamine on bile acid cholesterol metabolism in New Zealand rabbits with high cholesterol intake.
[Objective] To study the effects of colineamine on bile acid synthesis and cholesterol metabolism in New Zealand rabbits fed with high cholesterol for 4 weeks.
[Methods] Thirty New Zealand rabbits were randomly divided into control group, hypercholesterolemia model group and colineamine group with 10 rabbits in each group. Serum total cholesterol, low density lipoprotein (LDL), bile acid (bile acid) levels were measured and liver HMGCoA reductase activity, CYP7A1 activity, CYP7A1 mRNA, SHP mRNA, BSEP mRNA and LDL-R mRNA were measured after the suspension was given 20 ml for 4 weeks.
[Results] The serum total cholesterol and low density lipoprotein in the model group were higher than those in the control group (P < 0.01), while the serum total cholesterol and low density lipoprotein in the model group were lower than those in the model group (P < 0.01). There was no significant difference in bile acid level (P < 0.01). CYP7A1 activity and mRNA in model group were lower than those in control group (P < 0.01); CYP7A1 activity and mRNA in colineamine group were higher than those in model group (P < 0.01). HMGCoA reductase activity in model group was lower than that in control group (P < 0.01); HMGCoA reductase activity in colineamine group was higher than that in model group (P < 0.01). There was no significant difference between the model group and the control group (P > 0.05). The hepatic SHP mRNA and BSEP mRNA in the model group were higher than those in the control group (P < 0.01); the hepatic SHP mRNA and BSEP mRNA in the colineamine group were higher than those in the control group (P < 0.01) and lower than those in the model group (P < 0.01). And the model group increased (P < 0.01).
[Conclusion] Liver FXR activity, CYP7A1 activity and its mRNA, HMGCoA reductase activity, LDL mRNA decreased, serum cholesterol, LDL protein and bile acid increased in New Zealand rabbits fed with high cholesterol for a long time, while the activity of FXR, CYP7A1 activity and its mRNA, HMGCoA reductase activity, LDL mRNA increased, and serum cholesterol, LDL mRNA decreased with the application of colineamine. Cholesterol, low density lipoprotein and bile acid level remained unchanged.
【学位授予单位】：复旦大学
【学位级别】：博士
【学位授予年份】：2008
【分类号】：R341
【共引文献】
相关硕士学位论文 前1条
1 吕国平;FXR激动剂高通量药物筛选模型的建立及应用[D];河北师范大学;2007年
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