ObjectiveTo investigate the effects of the asphyxia as a Second Hit on renal function during early stage after birth in small for gestational age (SGA) infants.MethodsThe infants who were hospitalized within 24 hours after birth in Peking University Third Hospital between January 2013 and March 2015 were retrospectively enrolled, and divided into different groups depending on gestational age and asphyxia history. There were 40 preterm non-asphyxia SGA infants and 80 controls who were preterm non-asphyxia appropriate for gestational age (AGA) infants; 11 preterm asphyxia SGA infants and an equal number of preterm asphyxia AGA infants as controls; 33 term non-asphyxia SGA infants and 33 term non-asphyxia AGA infants as controls; and four term asphyxia SGA infants and 13 term asphyxia AGA infants as controls. Blood urea nitrogen (BUN), serum creatinine (SCr), and estimate glomerular filtration rate (eGFR) were tested within 48 h after admission and the incidence of abnormal indexes was compared between groups byt-test and Fisher exact test.Results(1) Compared with preterm non-asphyxia AGA group, BUN level significantly decreased in preterm non-asphyxia SGA group [(3.99±1.69) vs (5.11±2.08) mmol/L,t=2.948, P=0.004]. Compared with term non-asphyxia AGA group, term non-asphyxia SGA group had higher SCr level [(72.03±10.29) vs (62.58±12.27)μmol/L,t=3.390,P=0.001] and lower eGFR level [(25.19±4.07) vs (33.99±8.75) ml/(min·1.73 m2),t=5.238,P=0.000]. (2) Compared with preterm non-asphyxia AGA infants, preterm asphyxia AGA infants had higher BUN [(6.96±3.09) vs (5.11±2.08) mmol/L,t=2.602,P=0.011] and SCr [(76.45±10.11) vs (66.70±13.18)μmol/L,t=2.357,P=0.021] and lower eGFR level [(15.86±2.31) vs (19.54±5.08) ml/(min·1.73 m2),t=2.361,P=0.020]. Compared with preterm non-asphyxia SGA group, there was a significant increase in BUN level [(6.70±3.37) vs (3.99±1.69) mmol/L,t=2.581,P=0.025] and decrease in eGFR level [(14.80±4.67) vs (18.66±5.03) ml/(min·1.73 m2),t=2.285,P=0.027] in preterm asphyxia SGA group. Changes in term infants were similar to preterm infants. (3) Compared with asphyxia AGA group, asphyxia SGA group showed a higher frequency of abnormal eGFR in term infants (4/4 vs 4/13, Fisher exact test,P=0.029). ConclusionsAsphyxia as a probable Second Hit can influence the renal function during early stage in both preterm and term infants, especially in SGA infants.

Objective:To explore the hepatocyte insulin sensitivity of intrauterine growth retardation ( IUGR) rats and establish an insulin resistance cell model in vitro.Methods: An IUGR animal model was established by protein malnutrition during the mother pregnancy .On 60 d and 90 d after birth , the offspring rats were fasted for 12 hours and then their angular vein blood was collected to measure the fasting plasma glucose and fasting serum insulin level , then the insulin resistance index ( HOMA-IR) and insulin sensitivity index ( ISI) were calculated .The insulin sensitivity was evaluated by HOMA-IR and ISI.Primary hepatocytes from each group were respectively isolated by two-step perfusion with collage-nase and were defined as normal hepatocytes group and IUGR hepatocytes group .The normal hepatocyte group was divided into two groups: control group and insulin induction group .Insulin induction group was established by primary cultures of normal hepatocyte incubated with varying dilutions of insulin . CCK-8 was used to detect the viability of the cultured hepatocytes .Glucose oxidase-peroxidase method kit was used to measure glucose consumption of the hepatocytes .Results:HOMA-IR was significantly higher in IUGR rats than in the normal rats at the age of 60 days ( t=-17 .02 , P<0 .05 ) and 90 days ( t=-12.52, P<0.05).ISI was significantly lower than in the normal rats aged 60 days (t=5.61, P<0.05) and 90 days (t=12.42, P<0.05).There were no significant differences in hepatocyte viability among the control group , IUGR group and insulin induction group after incubation of 48 h on day 60 (F=1.34, P=0.29) and day 90 (F=0.22, P=0.81).The glucose consumption of the IUGR group and insulin induction group were significantly decreased compared with the control group on day 60 ( F=9.28, P=0.002) and day 90 (F=56.60, P<0.001), while there was no significant difference be-tween the IUGR group and insulin induction group (P=0.08, P=0.10).Conclusion:The insulin sen-sitivity of hepatocytes of IUGR rats decreased from adolescence to adulthood .High-dilution insulin may induce insulin resistance cell model in vitro.

Objective To investigate the effect of liver phosphatidylinosital 3-kinase/protein kinase B (PI3-K/AKT) pathway on the decrease of insulin sensitivity in fetal growth restriction (FGR) rats.Methods Twenty pregnant female rats were randomly divided into two groups one day after conception:normal-protein group and low protein group (n=10,respectively).Rats in low-protein group was given low protein diet (8.00％ protein) during pregnancy to build FGR model,while normal-protein group was given normal protein diet (20.00％ protein).On day 3,7,14,30,60 and 90 after birth,fasting blood samples of 8 male FGR offsprings from low-protein group and 8 normal offsprings from normal-protein group were collected to measure fasting plasma glucose and insulin level.Then insulin resistance index and insulin sensitivity index were calculated to determine insulin sensitivity.On day 7,14,30,60 and 90 after birth,liver tissue of 8 male FGR and normal offsprings were collected,insulin receptor substrate 1,2 (IRS1/IRS2)and glucose transporter 4 (GLUT4) mRNA expression were measured by real-time fluorescence polymerase chain reaction and the protein expressions of IRS1,PI3-K (subunit p110β),and AKT and phosphorylated AKT (pAKT) were measured by Western blot.The relationships between the expression changes of key molecules of PI3-K/AKT pathway and insulin sensitivity were analyzed by correlation and multiple linear regression method.Results (1) Mean birth weight of baby rats in low-protein group was significantly lower than that of normal-protein group [(4.92±0.36) g vs (6.43±0.59) g,t=14.73,P＜0.05].The incidence of FGR in low-protein group was 88.2％ (97/110); and for male offsprings,it was 94.1 ％ (48/51).(2) Compared to normal offsprings,fasting plasma glucose levels of male FGR offsprings were significantly higher from the age of 60 days to 90 days.Insulin levels and insulin resistance index were significantly higher and insulin sensitivity index was lower from the age of 30 days to 90 days,P＜0.05 respectively.(3) Compared to normal offsprings,IRS1 (0.45 ± 0.02 vs 0.68± 0.03,t=16.633,P＜0.05) and IRS2 mRNA (0.34±0.10 vs 0.70±0.19,t=4.864,P＜0.05) expressions in FGR offsprings were lower from day 7 after birth to day 90 (0.48±0.03 vs 0.59±0.05,t=5.237,P＜0.05; 0.49±0.20 vs 0.70±0.11,t=2.253,P＜0.05).There were no differences in expressions of GIUT4 mRNA and AKT protein between two groups (P＞ 0.05).IRS1,PI3-K and pAKT protein expressions of FGR offsprings decreased significantly from day 14 (0.22±0.05 vs 0.52±0.11,t=7.024,P＜0.05; 0.46±0.03 vs 0.97±0.08,t=17.508,P＜0.05; 0.62±0.10 vs 0.89±0.08,t=6.100,P＜0.05) to day 90 (1.11±0.08 vs 1.32±0.14,t=3.714,P＜0.05; 0.63±0.07 vs 1.00±0.19,t=5.206,P＜0.05;0.28±0.03 vs 0.45±0.10,t=4.880,P＜0.05).(4) The pAKT protein expression level of FGR rats was positively correlated with insulin sensitivity index (r=0.704,P＜0.05) ; while negatively correlated to the level of fasting plasma glucose (r=-0.609,P＜0.05),fasting insulin (r=-0.561,P＜0.05) and insulin resistance index (r =0.577,P＜ 0.05).Conclusions The changes of some key molecules' expressions of PI3-K/AKT pathway in liver might be involved in the insulin resistance in FGR rats.

OBJECTIVE:To study the in vitro antioxidant activity of chitosan(CTS)degradation derivatives and its preventive effects on drug-induced liver injury fibosis. METHODS:Acid hydrolysis method was used to prepare the CTS degradation deriva-tives CTS-3,CTS-6,CTS-8,CTS-10 for different hydrolysis time(3,6,8,10 h). The viscosity-average relative molecular mass and deacetylation degree of CTS and its degradation derivatives were determined,and its antioxidant activity was evaluated by de-tecting its in vitro scavenging ability on 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) and superoxide anion (O2-) radicals. Us-ing CTS-10 for in vivo liver injury fibosis prevention test,mice were randomly divided into normal control group(water),model group(water),CTS-10 high-dose,medium-dose,low-dose groups(100,50,25 mg/mL),8 in each group. Mice were intragastri-cally administrated 0.2 mL,then withdrawal after continuous 24 d. Then levofloxacin hydrochloride was intragastrically given for 7 d to establish drug-induced liver injury model(except for normal control group). Western blot method was used to detect the expres-sions of tumor necrosis factor α(TNF-α),transforming growth factor β1(TGF-β1)and Decorin protein in liver tissue of mice. RE-SULTS:The viscosity-average relative molecular mass of CTS,CTS-3,CTS-6,CTS-8,CTS-10 were 21.70×104,6.70×104,6.30× 104,5.01×104,4.87×104;and deacetylation degree were 83.44％,74.62％,67.28％,64.83％,54.23％,respectively. All of them had certain scavenging ability on DPPH and O2-,in which,CTS-10 was the strongest(25.47％ and 56.31％). Compared with nor-mal control group,expressions of TNF-α,TGF-β1 and Decorin protein in liver tissue in model group were enhanced (P<0.05). Compared with model group,expressions of TNF-α,TGF-β1 and Decorin protein in liver tissue in CTS-10 medium-dose and high-dose groups were weakened(P<0.01). CONCLUSIONS:The viscosity-average relative molecular mass and deacetylation de-gree of CTS-10 in CTS degradation derivatives are lower with stronger antioxidant activity,and show certain preventive effects on drug-induced liver injury fibosis in mice.

Objective To investigate the roles of phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway and its regulatory protein peroxisome proliferator-activated receptor γ (PPAR γ) and phosphatase and tension homologue deleted on chromosome 10 (PTEN) in regulating insulin sensitivity in rats with fetal growth restriction (FGR).Methods Sixteen pregnant rats were randomly divided into two groups including FGR and control groups on the 12th day of pregnancy (eight in each group).The FGR group was given low protein diet (8％ of casein) and restriction diet to establish the neonatal rat model of FGR.All maternal rats after delivery and newborn rats after weaning on 21 days after born were fed with normal diet.Each time blood samples were collected from eight newborn rats of each group to measure levels of fasting plasma glucose (FPG) and fasting insulin(FINS) at the time points of 21 days,two and four months after birth.Then insulin resistance index (IRI) and insulin sensitivity index (ISI) were calculated to evaluate insulin sensitivity.Expression of PI3K,AKT,PPAR γγ,PTEN and glucose transporters 4 (GLUT4) in skeletal muscle at mRNA and protein levels were measured at 21 days,two and four months after birth with real time fluorescence polymerase chain reaction and Western blot,respectively.Relationships between the expression of key molecules of PI3K/AKT signaling pathway and insulin sensitivity were analyzed.T-test,and Pearson's correlation analysis were used for statistical analysis.Results (1) The average birth weight of newborn rats in the FGR group was lower than that of the control group [(4.37± 0.69) vs (7.03±0.55) g,t=-20.75,P＜0.05].The incidence of FGR in the FGR group was 93.33％ (70/75).(2) Compared with normal offspring,those in the FGR group showed significantly increased FPG [two months after birth:(5.53± 0.58) vs (7.49 ± 0.38) mmol/L,t=8.08;four months afterbirth:(6.35±0.66) vs (8.94±0.90) mmol/L,t=6.58],FINS [two months afterbirth:(9.18±0.66) vs (14.67± 1.90) mU/L,t=7.71;four months after birth:(33.08±2.76) vs (56.33±2.81) mU/L,t=16.71] and IR1 (two months after birth:2.25±0.31 vs 4.90±0.81,t=8.63;four months after birth:9.30±0.90 vs 22.44±3.10,t=1 1.51),but decreased ISI (two months after birth:0.020 ± 0.002 vs 0.009± 0.001,t=-10.1 4;four months after birth:0.005±0.000 vs 0.002 ±0.000,t=-14.91) at two and four months after birth (all P＜0.05).(3) Compared with normal offspring,those in the FGR group showed decreased expression of PI3K (21 days after birth:0.082±0.028 vs 0.019±0.004,t=-6.29;two months after birth:0.020±0.003 vs 0.010±0.005,t=-4.78;four months after birth:0.014±0.004 vs 0.003±0.001,t=-7.87) and GLUT4 (21 days after birth:0.132±0.057 vs 0.041 ±0.019,t=-4.32;two months after birth:0.183±0.084 vs 0.069±0.017,t=-3.74;four months after birth:0.248±0.069 vs 0.113±0.040,t=-4.74) at mRNA level at 21 days,two and four months after birth (all P＜0.05).Compared with normal offspring,decreased expression of PPAR γ (two months after birth:0.028±0.002 vs 0.012±0.005,t=-3.70;four months after birth:0.030±0.008 vs 0.012±0.005,t=-3.80) and increased expression of PTEN (two months after birth:0.020±0.004 vs 0.045±0.014,t=5.09;four months after birth:0.023±0.007 vs 0.034±0.009,t=2.57) at mRNA level were observed in offspring of the FGR group at two and four months after birth (all P＜0.05).(4) Compared with normal offspring,expression of PI3K protein (21 days after birth:0.22±0.01 vs 0.17±0.02,t=-6.62;two months after birth:0.27±0.03 vs 0.16±0.02,t=-7.25;four months after birth:0.18±0.01 vs 0.09±0.02,t=-9.79) and GLUT4 protein (21 days after birth:0.21 ±0.01 vs 0.03±0.01,t=-27.29;two months after birth:0.10±0.01 vs 0.06t±0.01,t=-3.90;four months after birth:0.13 ±0.01 vs 0.08± 0.02,t=-8.10) decreased in offspring in the FGR group at 21 days,two and four months after birth (all P＜0.05).Compared with normal offspring,those in the FGR group showed decreased expression of PPAR γ protein (two months after birth:0.10 ± 0.01 vs 0.07± 0.01,t =-7.29;four months after birth:0.09±0.01 vs 0.08±0.01,t=-2.83),but increased expression of PTEN at protein level (two months after birth:0.10±0.01 vs 0.15±0.02,t=6.01;four months after birth:0.09±±0.01 vs 0.13±0.02,t=5.51) at two and four months after birth (all P＜0.05).(5) The IRI levels in offsprings in the FGR group were negatively correlated with the expression of PI3K,GLUT4 and PPAR γ at protein level (two months after birth:r=-0.90,-0.92 and-0.79;four months after birth:r=-0.92,-0.75 and-0.73,all P＜0.05),but positively correlated with the expression of PTEN at protein level (r=0.87 and 0.86,both P＜0.05) at two and four months after birth.Conclusions The abnormal expression of the key molecules of PI3K/AKT signaling pathway precedes the decrease of insulin sensitivity in newborn rats with FGR and the expression regulatory protein PPAR γ and PTEN are also changed,suggesting that these molecules may induce the impairment of insulin sensitivity in rats with FGR and be involved in the development of insulin resistance.

Objective To investigate the relationship between the expression of imprinted gene CDKN1C in placenta and the birth weight of neonates.Methods Twenty-nine term small for gestational age (SGA) neonates admitted to Peking University Third Hospital from January 1,2014 to December 31,2014 were recruited,and 29 appropriate for gestational age (AGA) neonates with a difference of not more than one week in gestational age served as controls.Fresh placental tissue was collected and the expression of imprinted gene CDKN1C mRNA in the placenta were detected by real-time fluorescence quantitative-polymerase chain reaction,and its protein expression was estimated by Western-blot.Chi-square test,independent-sample t test,Pearson's correlation analysis were used for statistical analysis.Results The CDKN1C mRNA expression level in SGA was significantly higher than that in AGA (0.133± 0.059 vs 0.100±0.046,t=2.401,P=0.020),so was the CDKN1C protein expression (0.280±0.043 vs 0.190±0.041,t=8.410,P=0.000).The CDKN1C mRNA expression levels were negatively correlated with birth weight in both groups (SGA group,r=-0.587,P=0.001;AGA group,r=-0.569,P=0.001),and the correlation was slightly stronger in SGA (r2=0.344) than in AGA (r2=0.324).The CDKN1C protein expression levels of the two groups were negatively correlated with birth weight (SGA group,r=-0.579,P=0.001;AGA group,r=-0.497,P=0.006),the correlation being stronger in SGA group (r2=0.335) than in AGA group (r2=0.247).The CDKN1C mRNA and protein expression levels of the two groups were negatively correlated with birth weight for gender,especially in males [mRNA:r2=0.293(male)vs r2=0.185(female);protein:r2=0.730 (male) vs r2=0.601(female)].Neither CDKN1C mRNA nor protein expression level was correlated to the placenta weight (mRNA:SGA group,r=0.119,P=0.540;AGA group,r=-0.069,P=0.722;protein:SGA group,r=0.126,P=0.515;AGA group,r=-0.247,P=0.196).Conclusions The expressions of CDKN1C mRNA and protein may be related to birth weight of term SGA neonates,especially in male infants.

Objective To investigate the pathogenic mechanism of Campylobacter jejuni(C.jejuni) associated with Guillain-Barré syndrome(GBS) and provide strategy for gene modification, the cstⅡ gene from 8 GBS-associated C.jejuni strains were compared with that from 3 GBS-unrelated C.jejuni strains, getting the base and amino acid mutations, the changes of secondary structures and finding the region which may be responsible for the pathogenicity of C.jejuni inducing GBS. Methods Three GBS-associated C.jejuni strains isolated from stools of GBS patients in north China were selected and cultured, which has been confirmed as GBS-associated by animal model. After sequencing the genome of them, the nucleotide sequences of cstⅡ gene were got through sequence alignment. The nucleotide sequences and deduced amini acid sequences of 3 GBS-associated cstⅡ genes were compared with that from 3 GBS-unrelated C.jejuni strains through bioinformatics software, getting the base and amino acid mutations, the changes of secondary structures. Other 5 GBS-associated cstⅡ genes were also aligned to know whether the differences we got above makes sense. In this way the genetic differences between two kinds of C.jejuni strains may be found and speculating the gene region related to the pathogenicity of GBS became possible. Results The cstⅡgene of 3 GBS-associated C.jejuni strains were all composed of 876 base pairs. Compared with GBS-unrelated C.jejuni strains, there were 9 consistent mutation sites in cstⅡ gene of LL and QYT stains, leading to 3 consistent amino acid mutation. The amino acid mutation of 114 and 182 sites in LL and QYT stains existed in other 5 GBS-associated C.jejuni strains. The sole amino acid mutation of ZHX strain -169 site, located near the 182 site. The seventh α-helix(165-180 region)of the secondary structure of the amino acid sequence from GBS-associated strains were shorter than that from GBS-unrelated strains, and the shorter regions were opened to form β-sheet or coli, which also existed in other GBS-related strains in this study.75% of the GBS-associated cstⅡ genes were Asn-51, while 25% of the GBS-associated and all of the GBS-unrelated cstⅡ genes were Thr-51.LL strain showed highly identity to other GBS-unrelated strains in this study. Conclusion The 165-180 segment of secondary structures in cstⅡ gene from local 3 GBS-associated C.jejuni strains are probably the responsible region involved in inducing GBS. The senior structure changes in this region may affect the activity of sialyltransferase and the structures of ganglioside epitope, so that the C.jejuni can acquire the pathogenicity of GBS. This finding may give a clue to genetic modified site. The bi-functional cstⅡ of C.jejuni may be related to the pathogenicity of GBS. The cstⅡ of LL strain to some extent represents the characteristics of Asian strains, which may directs strains monitoring.

Objective To investigate the regular pattern of dynamic changes of insulin sensitivity in fetal growth restriction (FGR) rats. Methods Twenty pregnant female rats were randomly divided into two groups as normal-protein group (NP) and low-protein group (LP), which respectively received normal protein diet (20% protein) and low protein diet (8% protein) during pregnancy. Weights of newborns were measured within 6 hours after birth, and the LP offspring whose birth weights were at least 2 standard deviations below the mean of NP offspring (≤2 standard deviations) were defined as FGR rats. At day 3, 7, 14, 30, 60 and 90 after birth, rats were fasted for 12 hours and then angular vein blood was collected to measure fasting plasma glucose (FPG) and fasting serum insulin (FINS) level. At 90 days of age, intraperitoneal glucose tolerance test (IPGTT)was performed; and blood triglyceride ( TG ), low-density lipoprotein cholesterol ( LDL-C ),high-density lipoprotein cholesterol (HDL-C) and glycosylated hemoglobin Alc (HbAlc) were measured. Insulin sensitivity was evaluated by FINS, insulin resistance index (HOMA-IR), insulin sensitivity index (ISI) and IPGTT. Results (1) Birth weights of LP offspring [(4. 92 ± 0. 36) g]were significantly lower than those of NP ones [(6. 43 ± 0. 59) g] (t = 14. 73, P＜0. 05). The incidence of FGR in LP was 88. 2% ; and for the male and female rats, the FGR rate was 94. 1% and 83. 1%, respectively. (2) FPG levels in the male FGR rats were significantly higher than in the NP from the age of 60 days [(9.38 ± 1.57) mmol/L vs (5. 58 ± 1.24) mmol/L] to 90 days [(8. 95 ±1.83) mmol/L vs (6. 21± 1.14) mmol/L] (t=-3. 291, P＜0. 05), while FPG levels in female FGR rats increased significantly only at 90 days of age [(9. 08±1.65) mmol/L vs (6.73±0. 67) mmol/L](t=-3. 226,P＜0. 05). FINS levels were significantly higher in FGR rats than in the NP from the age of 30 days (male FGR rats) or 60 days (female FGR rats) to 90 days (P＜0. 05, respectively).Similarly, HOMA-IR was significantly higher in FGR rats than in the NP at the age of 30 days (male FGR rats) or 60 days (female FGR rats) to 90 days (P＜0. 05, respectively). ISI in male FGR rats showed a reduction in comparison with the NP from the age of 30 to 90 days, while as to the female FGR rats it was significantly lower than in the NP only at 60 days of age and continued to 90 days (P＜0. 05, respectively). IPGTT showed that after injection of glucose, blood glucose at all four points (from 0 min to 120 min) in both male and female FGR rats were higher than that in the NP (P＜0. 05). (3) No significant difference was observed in TG, LDL-C and HDL-C at 90 days of age between the FGR rats and NP ones, while HbA1c in the male FGR rats was significantly higher than that in the NP [(7. 03±0. 54) % vs (4. 37±0. 64)%,t= -8. 028, P＜0. 05]. Conclusions FGR rats are able to maintain glucose balance and normal insulin levels during their earlier age, while insulin sensitivity decreased from adolescence to adulthood. The change of insulin sensitivity is different between male and female FGR rats, and male FGR rats are more likely to develop insulin resistance.

Objective To explore the effect of methylation of peroxisome proliferator-activated receptor γ(PPARy) gene promoter in liver and its mRNA expression changes on decreasing of insulin sensitivity in fetal growth restriction (FGR) rats.Methods Twenty pregnant rats were randomly divided into two groups on their first day of pregnancy:normal-protein group (NP) and low-protein group (LP),ten in each.During pregnancy the LP group rats were fed with low-protein diet (8.00％ protein),while the NP group rats were fed with normal-protein diet (20.00％ protein).The offspring rats were fed with standard feed after 21 days of birth.Male offsprings in NP group were as control offsprings,and male FGR offsprings in LP group ware as FGR offsprings.At day 3,7,14,30,60 and 90,fasting blood of offsprings was collected to measure fasting plasma glucose (FPG) and fasting insulin(FINS).Then insulin resistance index of homeostasis model assessment (HOMA-IR) and insulin sensitivity index (ISI) were calculated to evaluate insulin sensitivity.At day 7 and 90,liver tissue of male offsprings was collected to extract DNA and total RNA.The methylation level of PPARγ gene promoter and its mRNA expression were detected by methylation specific-polymerase chain reaction (MS-PCR) and reverse transcription-RCR,respectively.The relationships between methylation of PPARγ gene promoter and mRNA expression and insulin sensitivity were analyzed by Pearson correlation and nonparametric test method.Results (1) The mean offspring birth-weight of LP group was (4.92±0.36) g,which was lower than that [(6.43±0.59) g] of control group (t=14.73,P＜0.05).In LP group,the incidence of FGR offspring was 88.2％ (97/110) and the FGR incidence of male ones was 94.1％ (48/51).(2) At day 90,compared with control offsprings,FPG [(8.95±1.83) mmol/L vs (6.21±1.14) mmol/L,t=-3.291,P＜0.05],FINS [(59.57±9.89) mU/Lvs (36.10±7.32) mU/L,t=-4.916,P＜0.05] and HOMA-IR (0.967±0.297 vs 0.410±0.135,t=-4.472,P＜0.05) of FGR offsprings were significantly higher; while ISI of FGR offspring was lower than that of control offsprings (-3.043±0.294 vs -2.172±0.354,t=4.774,P＜0.05).(3) There was no significant difference in methylation degree of PPARγ gene promoter in liver between FGR and control offsprings at day 7 (0/8 vs 2/8,Fisher exact test,P＞0.05).The methylation degree of PPARγ gene promoter in liver in FGR offsprings was significantly higher than that of control offsprings at day 90 (8/8 vs 2/8,Fisher exact test,P＜0.05).Compared with control offsprings,PPARγ gene mRNA expression level of FGR offsprings decreased significantly at day 90 (4.3.07±7.51 vs 146.72± 40.66,t=7.09,P＜0.05).mRNA expression of PPARγ gene was the lowest in exhaustive methylation offsprings (27.2± 1.6),and then in partial methylation ones (47.3±33.0),the highest in no methylation ones (144.6 ± 21.2) (P＜0.05).(4) The correlation analysis showed that PPARγ mRNA expression level negatively correlated to the level of FPG (r=-0.819),FINS (r=-0.906) and HOMA-IR (r=-0.860),P＜0.05 respectively; but positively correlated to ISI level (r=0.947,P＜0.05).Conclusions Hypermethylation in promoter region of PPARγ gene might inhibit gene transcription,and be involved in the occurrence of insulin resistance in FGR rats.

Objective To explore the effects of folic acid and vitamin B12 supplement in maternal lactation on insulin resistance in fetal growth restriction (FGR) in rat offspring.Methods Eighteen Sprague-Dawley female rats and male rats were used.Pregnant rats were randomly divided into two groups at 12 days:normal-protein group (NP,n=6) and low-protein group (LP,n=12).The were 84 FGR newborn pups in LP group (93.3％,84/90).Forty-eight FGR newborn pups were randomly selected and divided into two groups (24 in each group):intervention group and non-intervention group.The intervention group was fed with high folate and vitamin B12 in the diet;and non-intervention group and NP group were fed normal diet.All of the newborn pups were weaned at 21 days after birth and then fed with normal diet.At days 21,60 and 120 d after birth,eight pups were randomly selected from each group and fasting plasma glucose (FPG),fasting insulin (FINS),blood diglyceride (TG) and cholesterol (TC) were measured.The insulin resistance index (IRI) and insulin sensitivity index (ISI) were calculated to evaluate insulin sensitivity.Variance and Student-Newman-Keuls tests were used for statistical analysis.Results (1) The incidence of FGR:Birth weight of LP offspring [(4.44±0.58) g] was significantly lower than that of NP ones [(7.03±0.56) g] (t=15.75,P ＜ 0.05).(2) FPG and FINS:at day 21 after birth,FPG of the non-intervention group,intervention group and NP group was (4.8±0.3),(4.8±0.4) and (4.6±0.3) mmol/L (F=0.57),respectively;FINS was (4.2± 0.2),(4.5 ±0.4) and (4.3 ±0.1) mU/L (F=0.31),respectively;and there was no significant difference among the three groups (both P ＞ 0.05).At day 60,FPG of the three groups was (7.5±0.4),(6.9± 1.0) and (5.5±0.6) mmol/L (F=17.14);FINS was (14.7± 1.9),(10.7± 1.0) and (9.2± 0.7) mU/L (F=38.34),respectively.At day 120,FPG was (8.9±0.9),(8.0±0.8) and (6.4±0.7) mmol/L (F=21.60);FINS was (56.3±2.8),(38.2±2.5) and (33.1 ±2.8) mU/L (F=164.46).FPG and FINS were highest in the non-intervention group,and lowest in NP group,with significant differences among the three groups of pups (all P ＜ 0.05).(3) IRI and ISI:at day 21,IRI of the non-intervention group,intervention group and the control group was 0.9±0.1,0.9±0.1 and 0.9±0.2 (F=0.49);ISI was-(3.0±0.7),-(3.0±0.1) and-(3.0±0.3) (F=0.69);and there was no significant difference among the three groups (both P ＞ 0.05).At day 60,IRI of the three groups was 4.9±0.8,3.3±0.3 and 2.2±0.3 (F=49.48);ISI was-(4.7±0.2),-(4.3±0.1) and-(3.9±0.1) (F=63.47).At day 120,IRI of the three groups was 22.4±3.1,13.6±2.0 and 9.3±0.9 (F=75.15);ISI was -(6.2 ± 0.1),-(5.7 ± 0.1) and-(5.3 ± 0.1) (F=104.42);and there were significant differences among the three groups (all P ＜ 0.05).(4) TC and TG:at day 21,TC of the non-intervention group,intervention group and the control group was (2.0±0.1),(2.0±0.1) and (2.0±0.1) mmol/L (F=0.10);TG was (0.75±0.1),(0.77±0.1) and (0.74±0.1) mmol/L (F=0.33);and there was no significant difference among the three groups (both P ＞ 0.05).At day 60,TC of the three groups was (2.3 ± 0.1),(2.2 ± 0.1) and (2.0± 0.2) mmol/L (F=8.34);TG was (1.5 ± 0.2),(1.2±0.1) and (1.0±0.2) mmol/L (F=17.93).At day 120,TC was (2.4±0.2),(2.2±0.1) and (2.1 ±0.1) mmol/L (F=6.12);TG was (1.7±0.5),(1.2±0.3) and (l.0±0.1) mmol/L (F=9.80).The TC and TG were highest in the non-intervention group and the lowest in the control group;and there were significant differences among the three groups (all P ＜ 0.05).Conclusion Supplementing folic acid and vitamin B12 in maternal lactation can improve in some extent insulin resistance in FGR rats,but not sufficient enough to completely repair glucose and lipid metabolism.