Expression Of Vaspin In Rats Induced By High Fat Diet And Study Of Gestational Diabetes

BackgroundWith the continues improvement of living standards and the corresponding changes in lifestyle,the obesity and incidence of GDM increased year by year.High fat,high sugar diet and less physical training is considered to be important factors to induced to GDM.Gestational diabetes mellitus(GDM),a common pregnancy complication,is defined as glucose intolerance with onset or first recognition during pregnancy.The influence of GDM on the health of mothers and babies should not be ignored,and GDM is closely related to a variety of adverse pregnancy outcomes.At present the etiology of GDM is unclear.GDM is a metabolic disease caused by a variety of factors and the most important pathophysiological mechanism of GDM is considered to insulin resistance.As pregnancy advances,IR becomes more and more intense and GDM may occur when a woman's pancreatic function is not sufficient to overcome the diabetogenic environment of pregnancy.Nowadays numerous studies implicated adipose tissue in the regulation of insulin resistance through excretion of adipokines.Visceral adipose tissue-derived serpin A12(vaspin),is a novel adipokine with potential insulin-sensitizing effects.Previous studies have indicated vaspin is in-depth research in obesity,IR and T2DM.GDM is often combined with obesity,IR and abnormalglucose and lipid metabolism.However,research related to vaspin and is rarely and the understanding of vaspin in GDM is still controversial.The experiment establish a gestational diabetes rat model by feeding high fat diet This study observe the vaspin mRNA and protein expression of visceral adipose to discuss the relation between the expression of vaspin and the paraments of gestational diabetes mellitus.In this way,we can further study the pathogenesis of gestational diabetes mellitus.Objectives To explore the effects of vaspin on glucose,lipid metabolism and IR,the experiment established a gestational diabetes rat model by feeding high fat diet and observed the changes of serum vaspin levels and mRNA and protein levels of vaspin in adipose tissue in pregnant rats induced by high fat diet and normal diet and non-pregnant rats.Methods A total of 55 female SD rats(160-180g)were selected and divided into four groups:normal diet virgin rat(NV)group,fat diet virgin rat(FV)group,normal diet pregnant rat(NP)group and fat diet pregnant rat(FP)group.Three months later,the female rats of NP,FP groups were put into the same cage with the male rats at the ratio of 2:1 to conceive.Then the rats were given high fat diet or normal diet as usual.Three months before conception and pregnancy 1,7,14,20days,the body weight and fasting plasma glucose of rats were measured.The serum fasting insulin and serum c-peptide levels was measured using enzyme immunoassay throughout pregnancy dynamically,measuring insulin resistance index,insulin ?cell index and insulin sensitivity index.At the third trimester of pregnancy glucose tolerance,the indicator of fat and fasting serum vaspin levels were tested.Correlations were analyzed between vaspin and indexes of glucose and lipid metabolism and HOMA.Liver and pancreas were dyed to observe under microscope.The mRNA and protein levels were detected using RT-PCR,Western blot and immunohistochemical staining in visceral adipose tissue of rats.Results(1)After raised by high fat diet,the body weight of rats increased distinctly and during pregnancy this circumstance enhanced(252.99±21.13 vs.188.3±21.77,P<0.05).Pregnancy 1,7,14,20days,the body weight of high fat group was higher than that in other 3 groups(335.62±29.03 vs.307.79±23.54 vs.274.6±22.45 vs.297.21±28.72 P<0.05).(2)The FP group rat's fasting glucose was higher than NP group(5.43±0.69 vs.4.69±0.73;5.23±0.5vs.4.78±0.35;5.27±0.51vs.4.85±0.14,P<0.05).The blood glucose levels are reached the maximum in 30 min.The area under curve of IPGTT in FP group rat was lager than other groups(14.95±0.81 vs.12.04±1.68 vs.10.7±0.29 vs12.48±1.14,P<0.05).(3)The levels of serum lipids in FP group rat were higher than normal diet rats(P<0.05).(4)Fasting insulin and Serum C-peptide were significantly increased.With the increase of insulin secretion,the FP group rat's insulin resistance was evident compared with the NP group(P<0.05),but insulin sensitivity was lower compared with the NP group The liver of the rats fed by high fat diet had fat accumulation and pancreas islet cell has the state of hyperplasia.(5)The serum vaspin levels of FV group rats were the highest in four groups.The serum vaspin levels of FP group rats were higher than NP group rats but there is no statistical significance in 4 groups of serum vaspin levels(22.83±1.33vs21.68±4.27vs19.03±3.17vs16.78±4.5n,P>0.05).(6)Correlations analysis of serum vaspin levels and indexs:Serum vaspin was negatively correlated with HOME-IR in FP group(r=-0.8,P<0.5).Serum vaspin was positively correlated with TG in FV group(r=-0.92,P<0.5).Serum vaspin was positively correlated with body weight in NV group(r=0.91,P<0.5).(7)Compared with the other three groups,the FP group rats visceral adipose increased.The mRNA and protein expression levels of vaspin in FP group rats were higher than NP group rats and NV group rats,but lower than FV group(3.53±0.93 vs.2.02±0.31 vs.1.5±0.34 vs.4.9±0.26;0.85±0.02 vs.0.94±0.03 vs.0.72±0.02vs1.23±0.06,P<0.05)?(8)The transcription of vaspin,PI3K and IRS1 gene have same tendency of the protein expression level in Visceral adipose tissue,the tendency was not observed in other tissues.The expression of PI3K is not closely related to IRS1.(9)GRP78[(409.97)pg/mL vs.(219.18+ 145.32)pg/mL],weight at the time of execution[(350.45+50.37)g vs.(316.94+44.50)g]and overall weight gain[(197.97+52.77)g vs.(158.83+51.16)g],HF group was significantly higher than NC group(P<0.05).Fasting blood glucose(FPG)[(5.74+0.61)mmol/L vs.(4.70+0.39)mmol/L]and 2-hour postprandial blood glucose(2h_PG)[(7.43+0.411)mmol/L vs.(5.63+0.36)mmol/L],body weight[(327.2+ 48.99)g vs.(256.00+4.62)g]HF group was higher than NC group(P<0.05).(10)GRP78 levels were negatively correlated with diet,weight at the time of execution,TCH,f-chol,TG,hdl-c,ldl-c and NEFA,and overall weight gain was negatively correlated(r=-0.362,-0.348,-0.439,-0.420,-0.419,-0.284,-0.358,-0.346,-0.295),and positively correlated with pre-pregnancy FPG,pre-pregnancy 2h_PG,gestational 1h_PG,and pre-execution FPG(r=0.330,0.492,0.324,0.289).(11)in the hyperlipidemic group,GRP78 was negatively correlated with 1h_PG,2h_PG,pre-pregnancy weight,weight at the time of execution,TCH,f-chol,TG,ldl-c,NEFA and overall weight gain,and positively correlated with 1h_PG in early pregnancy and FPG before execution.In the NC group,GRP78 was negatively correlated with gestational week,weight at the time of execution,TCH,f-chol,TG,hdl-c,and NEFA(r=-0.353,-0.370,-0.427,-0.422,-0.402,-0.458,-0.493),and was positively correlated with gestational weight in late pregnancy,2h_PG,FPG in late pregnancy,and 1h_PG in late pregnancy(r=0.661,0.488,0.658,and 0.861).(12)The GRP78 level is different between the unpregnant group and the middle pregnant group(P<0.011).GRP78 levels were significantly different between HF group and NC group at different gestational days(P<0.05).In HF group,GRP78 was correlated linearly with gestational days(r2=0.98).The GRP78 of NC group showed correlation with gestational age(r2=0.78).Conclusions:(1)The gestational diabetes rat model induced by high fat diet was successfully established The model presented major pathophysiological manifestations of GDM,and can be used as a good model of GDM in relevant research.(2)The expression of vaspin is related to obesity,IR,glucose and lipid metabolism.Vaspin may also play a role in GDM.The higher levels of vaspin in The gestational diabetes rats induced by high fat diet which might be explained by a compensative increase of insulin-sensitizing vaspin inattempt to ameliorate increased IR in GDM.It might increase at the early stage of diabetes,but it decreases with the worsening of the IR(3)There is no correlation between vaspin and IRS 1,PI3K,and the increase of vaspin will not lead to insulin resistance of GDM.The vaspin expression was higher in GDM serum and visceral fat tissue,it was the result of an interactive effect between vaspin and the fat consumption,rather than the cause of insulin resistance.(4)The expression levels of Vaspin and IRS1,PI3K and gene transcription were not completely consistent.Only higher consistency was observed in visceral fat tissue,it is suggested that there may be some regulatory mechanism between transcriptional level and protein expression level in other tissues.These regulatorymechanism lead to complex changes in vaspin and PI3K/IRS1 pathways.Perhaps only vaspin in visceral fat tissue can act directly on the PI3K/IRS1 pathway without interference.Therefore,vaspin in visceral fat tissue plays an important role in the development of GDM.(5)GRP78 secretion is increased,in order to improve insulin resistance,which caused by high-fat obesity and restore ER homeostasis.GRP78 is related to blood lipids closely,and GRP78 decreases gradually with the progress of pregnancy,which may be the cause or result of insulin resistance in pregnancy.6.ER stress and its signaling networks are emerging as potential sites for inflammatory and metabolic diseases,GRP 78 may be a candidate for therapeutic application.Objective To investigate of demographic characteristics,the pregnancy complications and outcomes in the patients with previous gestational diabetes mellitus(PGDM),gestational diabetes mellitus(GDM)and normal glucose tolerance(NGT)in Kunming,and to guide the women with diabetes before pregnancy and reduce the occurrence of adverse outcomes.Methods Collected the information of 28,275 single pregnancies in**hospital from January 1,2005 to December 31,2013.Comparison of maternal demographic characteristics,age,height,weight,educational levels,BMI,family history of diabetes,maternal-fetal outcomes and pregnancy complications among the 3 groups.Results After standardized treatment,the weight gain of PGDM and GDM groups were lower than NGT group(p<0.001)during pregnancy.The incidence of maternal advanced age,overweight,and the values of HbA1C and BMI of GDM and PGDM groups were significantly higher than NGT group(p<0.001),and PGDM was higher than the GDM group(p<0.05).The incidence of cesarean delivery,preeclampsia,gestational hypertension disease,LGA,macrosomia,preterm,admit to NICU,neonatal hypoglycemia,hyperbilirubinemia of PGDM and GDM groups were significant difference between the three groups,PGDM group was highest(p<0.001).Conclusion Even received standardized treatment,the perinatal outcomes of PGDM group are significantly poorer the GDM and NGT groups,thus we should emphasize the importance of recognizing PGDM at early pregnancy or before pregnancy.