论文标题:牛磺酸对模型大鼠糖尿病肾病防治作用的实验研究
Experimental Investigation on Taurine"s Preventive or Therapeutic Effects on Diabetic Nephropathy in Diabetic Rats
论文作者 梁纪伟
论文导师 田庆伟,论文学位 硕士,论文专业 营养与食品卫生学
论文单位 天津医科大学,点击次数 88,论文页数 62页File Size4862k
2004-05-01论文网 http://www.lw23.com/lunwen_676240292/ 牛磺酸,抗氧化,脂质代谢,糖尿病肾病,胰岛素,并发症,血糖
Taurine,Anti-oxidation,Lipid metabolism,Diabetic nephropathy, Insulin, Complication, blood sugar
目的：目前对于糖尿病的研究，除了在临床上积极研制新的药物，努力提高临床治疗效果的同时，其研究的热点越来越倾向于如何预防或延迟糖尿病的发生以及防治糖尿病的各种并发症上。而部分功能性食品，不仅在某些食物中含量丰富，价廉而易被人们接受，而且无任何毒副作用，并具有多种生物学功效，己逐渐成为预防医学中对于各种慢性病防治作用的研究重点。牛磺酸(Taurine，Tau)，又名2-氨基乙磺酸，是哺乳动物组织细胞中含量较为丰富的一种含硫β-氨基酸，自1975年Hayes等发现其在膳食中缺乏可致猫视觉功能减退，确立其在营养学中地位至今，大量国内外研究及临床应用发现，Tau具有广泛的生理学功效，是调节机体正常生理功能的重要物质，在抗肿瘤、抗衰老、调节免疫及防治肝肾疾病等方面，具有多种药理学作用。迄今，有关牛磺酸对糖尿病及其并发症防治作用的研究，取得了可喜的成果，但对于糖尿病肾病的防治作用，研究较少，且结论并不完全一致，作用机制也尚未明确。本文在以往研究的基础上，通过观察Tau对链脲佐菌素(streptozotocin，STZ)所致的大鼠糖尿病肾病模型的防治作用，从生化、免疫、抗氧化系统、细胞凋亡等方面进行研究分析，旨在探讨Tau对糖尿病，尤其是糖尿病肾病防治方面的作用机理及应用前景。方法：雄性SD大鼠，体重250～350g，购进后平衡饲养一周，按体重随机分为对照组(Control，12只)、实验组(48只)。将实验组大鼠经尾静脉注射50mg／kg·bw链脲佐菌素，对照组大鼠经尾静脉注射等量的柠檬酸盐缓冲液，72h后剪尾采血，测定动物空腹血糖，以血糖≥11.1mmol／L、动物出现明显的多饮、多食、多尿症状作为糖尿病模型大鼠标准，未达标准动物不纳入实验。然后，将糖尿病模型大鼠按血糖水平高低，进行随机区组法 Abstraet in Chinese分组:糖尿病模型组(DM组)、1%牛磺酸组(1%几u组)、2%牛磺酸组(2%几u组)、3%牛磺酸组(3%lhu组)，每组H只，动物自由饮食，Control组和DM组大鼠喂饲正常饲料，其他实验组饲料中分别添加Thu使其含量为1%、2%和3%，至实验结束，共观察12w。从实验开始，前两周每周检测体重两次，自第3w始，每周检测体重一次，给予牛磺酸sw后，收集动物24h尿，检测尿量及尿总蛋白含量;经内毗静脉丛取血lml，测血清肌配(Cre)、尿素氮(BL〕N)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL一C)、甘油三酷(TG)含量。至12w末，股动脉放血处死动物，称取动物脾脏、胸腺、肾脏、肝脏的重量，计算其脏器系数;取胰腺、肾脏组织送做病理，观察组织学改变;测定尿，Q.蛋白(UTP)、血清胰岛素(取S)、Cre、BIJN、TC、LDL一C、TG、丙二醛(MDA)含量及超氧化物歧化酶(S OD)、谷胧甘肤过氧化物酶(GsH一Px)活性。结果:(l)体重变化情况实验过程中，Conirol组大鼠体重自第Zw末开始增加(P二0.013)，每周增重约13一23克;DM组大鼠体重自造模后即出现体重减轻，但在实验进程中各期体重变化并不明显;1%丁hu组动物体重自第lw开始减轻，至第sw开始升高，但实验末体重仍低于基础体重(P<0 .05)，2%和3%丁hu组大鼠体重自第lw均开始减轻，至实验中期开始升高，但各期差别无显著性。(2)血糖及血清胰岛素水平模型制备和实验sw后，DM组与各实验组动物血糖差别无统计学意义，但各组均高于Conirol组(尸<0.05)，至实验结束，各实验组均可不同程度地降低血糖浓度 (与DM组相比，差别均具有显著性，P<0.05)，但均未降至正常水平(与Control组相比，差别仍具有显著性，·p<0.05);实验末DM组大鼠血清胰岛Abstraet in Chinese素含量明显低于Control(P<0 .05)，3%几u组血清胰岛素的含量显著升高 (P<0.05)，且与Control组相比已无显著性差异。(3)脏器系数实验末，不同实验组可不同程度地降低增大的肝、肾脏器系数，2%和3%几u组与DM组相比，差别具有统计学意义，但脏器系数仍高于Control组(尸<0.05);DM组胸腺脏器系数较Control组明显降低(P<0 .05)，只有2%几u可使其有所升高(尸<0.05);脾脏脏器系数在各组间均无显著性差异。(4)血脂测定结果实验中期，DM组与1%几u、2%J么u组血清TG含量均高于Control组(P<0.05)，而3%Tau组血清TG含量与C。爪rol组相比差别无显著性;与Control组相比，除2%丁hu组外，其余各组血清TC含量均明显升高 (尸<0 .05);而LDL一C在各组中差别无统计学意义。至实验末，DM组和l%Thu组血清TG含量与Control组相比差别具有显著性，而中、高几u剂量组差别已无统计学意义;各实验组均可使TC血清含量降至Control组水平;LDL一C含量在各组中差别仍无显著性。(5)肾功能变化sw末DM组大鼠血清BIJN、Cre及尿UTP含量明显高于COntrol组(P<0.05)，1%和2%lhu可使三者含量有所降低，但与COntrol组相比，差别仍具有显著性，3%丁hu可使血清BUN和Cre含量降至Conirol组水平，但尿UTP含量仍高于Conirol组动物(P< 0.05)。实验末，除1%几u不能使UTP降至Contr01组水平外，其余各组均使三者含量降至Control组水平。(6)抗氧化指标测定结果实验末，DM组动物肾组织匀浆SOD、GsH一Px活性较Cont
Objective: At present, studies on diabetes mellitus (DM) are more and more focused on how to delay the episode of DM and how to prevent or therapy kinds of complication of DM, besides manufacturing new medicine and dedicating to improve the effect of clinical therapy. While some functional foods are gradually becoming the searching focus of preventive medicine, because they are cheap, abundant in foods and have many biological effects without ill effect. Taurine (Tau), chemically named 2-aminoethanesulfonic acid, is an important sulfur-containing amino acid that is widely distributed in various mammal tissues. Since it was discovered by Hayes in 1975, many experimental studies and clinical applications have suggested it has important physiological action and have beneficial effects on antitumor, antisenium, adjusting immunity and preventing or curing hepatopathy and nephrosis. Although the investigations on Taurine" preventive or therapeutic on.DM or its complications have achieved great progress, few study on its effects on diabetic nephropathy is undertaken and its mechanism is not clear. On the basis of the previous investigations, we examined the preventive or therapeutic effects and possible chemopreventive mechanism of taurine on streptozotocin (STZ)-induced diabetic nephropathy inrats in order to explore the perspective on clinical application.Methods: Male Sprague-Dawley (SD) rats weighing 250~350g, were acclimatized for 1 week prior to being divided randomly according to weight into control group (12) and experimental group (48). DM was induced by a single caudal vein injection of STZ (50mg/kg-bw) while the control group animal was injected equivalent citrate buffer and fed a standard rat chow diet. Diabetes was defined as fasting plasma glucose greater than ll.lmmol/L in caudal vein blood and rats have the symptoms of polyuria, polyphagia, and emaciation. Then all the DM rats were divided randomly according to plasma glucose into the following group: (1) DM group: diabetic group with 12-week duration of diabetes fed a standard rat chow diet; (2) l%Tau group: diabetic group with 12-week duration of diabetes fed the above-mentioned diet containing 1% taurine; (3) 2%Tau group: diabetic group with 12-week duration of diabetes fed the above-mentioned diet containing 2% taurine; and (4) 3%Tau group: diabetic group with 12-week duration of diabetes fed the above-mentioned diet containing 3% taurine. Food and water were given ad libitum to all animals. Monitoring the weight of all rats every week during the test and the following indexes were examined at the end of 5th week: 24h urine volume, UTP, Cre, BUN, TC, LDL-C, TG. At the end of the test, rats from each group were killed by bleeding the femoral artery and the serum insulin, Cre, BUN, TC, LDL-C, TG, MDA, UTP and the activity of SOD and GSH-Px were examined. Recorded the weight of spleen, thymus, liver, kidney, and the tissue changes of their kidneys and pancreases were observed by microscope.Results: (1) Animal weight: Since the second week, the weight of control group rats began to increase by 13~23g every week. While the weight of DM group rats began to decrease since 1st week but the difference is insignificant. The weight of all the other three experimental group rats began to decrease first and increase since the metaphase, but the difference at different phase is insignificant. (2) Blood sugar and serum insulin: The blood sugar of control group rats is significantly lower than all the other groups at the beginning of test or at the end of 5th week. At the end of the test, the blood sugar of all the three Tau group is significantly lower than that of the DM group, but still is significantly higher than that of the control group. On the other hand, the insulin in serum of DM group is significantly lower than control group, though only 3%Tau can increase the serum insulin and the content of insulin in serum of 3%Tau group is already no lower than the control group. (3) Organ/body ratio: At the end of the test, the organ/body ratio of the live
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