Effects of folic acid and vitamin B12 on insulin resistance of fetal growth restriction rats / 中华围产医学杂志

ABSTRACT

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 daysnormal-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 FGRBirth 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 FINSat 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 ISIat 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 TGat 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.