| Objective: This study induced type 2 diabetes model through high fatdiet add intraperitoneal injection streptozotocin (STZ).Then observe the effectof gastric bypass surgery on type 2 diabetes mellitus and normal SD ratsThrough the change of fasting blood glucose、fasting plasma insulin、serumlipid and insulin resistance index in pre-and post-operative. In eight weeksof post-operative, the gene expression of glucose transporter-4(GLUT-4) inadipose tissues and skeletal muscle was measured too. Preliminary discussionthe mechanism of improvement of insulin resistance and GLUT-4 mRNAexpression after surgery.Methods: Male SD rats (construction)were fed by high fat diet for 8weeks (week, W),then were made to type 2 diabetes(T2DM) model byintraperitoneal injection STZ (30 mg/kg).twenty T2DM model and twentynormal SD rats were randomly divided into T2DM gastric bypass surgery(DRO group)、T2DM sham operation (DSO group)，Normal SD rats gastricbypass surgery (NRO group) and normal SD rats sham operation (NSOgroup),each group have10 rat only. Fasting plasma glucose(FBG), Fastingserum insulin( Fins), bloodlipid and insulin resistance index (IR) weremeasured in pre-operative and in four、eight weeks of post-operative.In eighthweeks of post-operative,all rats were put to death ,then use reversetranscription polymerase chain reaction( RT-PCR) method to detect the GLUT-4 mRNA expression in adipose tissues and skeletal muscle.Results:1.The change of FBG pre- and post-operative:in preoperative, the FBGof diabetes group(DRO group and DSOgroup) was higher than normalgroup(NRO group and NSOgroup);In four weeks of post-operative the FBGof DRO group decreased from (22.24±4.13)mmol/l to( 18.93±3.76) mmol/L（P<0.05）, but there was no difference between DRO group and DSO groupin the corresponding time. In eight weeks of post-operative ,The FBG furtherreduced to 9.40±2.49 mmol/l（P＜0.05),that was markedly lower than thatDSO group in the corresponding time（P＜0.05）; the FBG of DSO group、NRO group and NSO group itself had no obviously changes between pre- andpost-operative(P>0.05).2.The Fins level in pre- and post-operative: In preoperative, the Fins ofdiabetes rats (DRO group and DSOgroup)was higher than that of normalrats(NRO group and NSO group); In four weeks of postoperative,the Fins ofDRO group decreased from (22.56±3.68)mIU/Lto进制(19.83±3.94)mIU/L(P<0.05),but there was no statistical significanc compared with DSO group inthe corresponding time (P>0.05), in eight weeks of post-operative, the Finsfurther decreased to (6.79±2.52) mIU/L,that was markedly lower than DSOgroup(P<0.05) and have no difference between DRO group and NRO groupin the corresponding time;the Fins of DSO group、NRO group and NSO groupitself showed no significant change between pre-and post-operative.3. The HOMA-IR pre- and post-operative: In pre-operative, theHOMA-IR of diabetes rats(DRO group and DSOgroup) were markedly higherthan that of normal rats(NRO group and NSO) (P<0.05);In four weeks ofpost-operative,The HOMA-IR in DRO group decreased from(22.73±7.59) to(16.59±5.48) (P<0.05),but there was no difference compared with DSOgroup in the corresponding time (P>0.05);In eight weeks of post-operative,theHOMA-IR of DRO group fuether decreased to(7.23±2.69) ,that was lowerthan that of DSO group in the corresponding time (P<0.05),and there was nodifference between DRO group and NRO group in the correspondingtime;The HOMA-IR in DSO group、NRO group and NSO group itself had nosignificant changes between pre-and post-operative .4.The level of bloodlipid pre- and post-operative: before surgery, thelevel of TG and TC of diabetes rats(DRO group and DSOgroup) weremarkedly higher than that of normal rats(NRO group and NSO) (P<0.05); Infour weeks of post-operative,the TG of DRO group decreased from(2.32±0.20) mmol/L to (1.61±0.44) mmol/L(P<0.05),that was lower thanDSO group in the corresponding time(P<0.05), and further decreased to(1.02±0.32)mmol/L in eight weeks of post-operative; In four weeks ofpost-operative, the TC of DRO group decreased from (1.80±0.29)mmol/L to(1.56±0.23)mmol/L (P<0.05),that was lower than DSO group in thecorresponding time(P<0.05), and have no difference between DRO group andNRO group(P>0.05)；the level of TG、TC in NRO group and NSO groupitself had no significant change between pre- and post-operative.5.The gen expression of GLUT-4 in rats adipose tissue in eight weeks ofpost-operative : The GLUT-4mRNA expression of adipose tissue in DROgroup was (0.87±0.17), that of DSO group was(0.62±0.10, DRO group washigher than DSO group(P<0.05),but there were no significant differencebetween DRO group and NRO group or NSOgroup (P＞0.05). TheGLUT-4mRNA expression of adipose tissue in NRO group was (0.94±0.16), NRO group was higher than DSO group(P<0.05),but there were nosignificant difference between NRO group and NSOgroup (P＞0.05).6. The gen expression of GLUT-4 in rats skeletal muscle in eight weeksof post-operative: The GLUT-4mRNA expression of adipose tissue in DROgroup was (2.53±0.18), that of DSO group was(1.21±0.11), DRO group washigher than DSO group(P<0.05),but there were no significant differencebetween DRO group and NRO group or NSOgroup (P＞0.05). TheGLUT-4mRNA expression of adipose tissue in NRO group was (2.59±0.19),NRO group was higher than DSO group(P<0.05),but there were nosignificant difference between NRO group and NSOgroup (P＞0.05).Conclusion:1. The study found that the type 2 diabetes model established byconjunctive low-dose of SZT and high fat diet have obvious insulin resistanceand higher FBG, that is a good model of T2DM.2. After eight weeks of surgery,the FBG, Fins , HOMA-IR and serumlipids of gastric bypass group were significantly lower than that ofpreoperative and shame operation in diabetic rat ,even can reach to normallevels, so the gastric bypass surgery have evident effects on type 2 diabeticrats.3. After eight weeks of surgery, the GLUT-4 mRNA express in adiposetissue and Skeletal muscle of gastric bypass surgery group was significanthigher than sham group in diabetic rat , and even reach to normal levels,butfor normal rat there were no influence. |
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