Fetal Growth Restriction Rats Research Articles

Leptin deficiency, a potential mechanism for impaired fetal lung development in uteroplacental insufficiency?

Uteroplacental insufficiency (UPI) is a major cause of fetal growth restriction (FGR). Leptin, an adipokine, has been shown to play a vital role in fetal organogenesis. There is evidence reporting leptin deficiency in preterm and growth-restricted fetuses. In this issue of Pediatric Research, Yuliana et al. report leptin expression and lung development in UPI-induced FGR rats. UPI-induced FGR rats expressed decreased lung leptin and had impaired lung development, as shown by decreased surface area and lung volume. They also found a significant association between lung radial alveolar count, serum leptin, von Willebrand factor, and specific metabolites on metabolomic analyses. Previous studies on leptin supplementation in vivo have been associated with improvement in lung maturation; supporting the evidence, that leptin improves lung growth and development in FGR and may have future therapeutic potential in the improvement of respiratory outcomes in these infants. Future studies to support evidence of this association in humans are warranted.

Maternal Protein Restriction Inhibits Insulin Signaling and Insulin Resistance in the Skeletal Muscle of Young Adult Rats.

Infants with fetal growth restriction (FGR) are at a risk of developing metabolic syndromes in adulthood. We hypothesized that skeletal muscle degeneration by nutrition-restricted FGR results in abnormal insulin signaling and epigenetic changes. To develop a protein-restricted FGR model, rats were fed a low-protein diet (7% protein) during the gestational period; rats fed a normal diet (20% protein) were used as controls. At 8 and 12 weeks of age, the pups were subjected to oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) to evaluate insulin resistance. At 12 weeks, the mRNA and protein levels of insulin signaling pathway molecules in the skeletal muscles were examined. DNA methylation of promoters was detected. DNA extracted from skeletal muscles was used as a template for methylation-specific PCR analysis of GLUT4. The body weight of FGR rats from birth to 8 weeks was significantly lower than that of the controls; no significant difference was observed between the groups at 12 weeks. In the OGTT and ITT, the incremental area under the curve (iAUC) was significantly higher in FGR rats than in the controls at 12 weeks. The mRNA and protein levels of Akt2 and GLUT4 in the plantar muscles were significantly lower in FGR rats than in the controls. GLUT4 methylation was comparable between the groups. Protein-restricted FGR rats showed insulin resistance and altered insulin signaling in skeletal muscles after 12 weeks. However, we could not demonstrate the involvement of DNA methylation in this model.

The Gut Microbiota of Pregnant Rats Alleviates Fetal Growth Restriction by Inhibiting the TLR9/MyD88 Pathway.

Fetal growth restriction (FGR) is a prevalent obstetric condition. This study aimed to investigate the role of Toll-like receptor 9 (TLR9) in regulating the inflammatory response and gut microbiota structure in FGR. An FGR animal model was established in rats, and ODN1668 and hydroxychloroquine (HCQ) were administered. Changes in gut microbiota structure were assessed using 16S rRNA sequencing, and fecal microbiota transplantation (FMT) was conducted. HTR-8/Svneo cells were treated with ODN1668 and HCQ to evaluate cell growth. Histopathological analysis was performed, and relative factor levels were measured. The results showed that FGR rats exhibited elevated levels of TLR9 and myeloid differentiating primary response gene 88 (MyD88). In vitro experiments demonstrated that TLR9 inhibited trophoblast cell proliferation and invasion. TLR9 upregulated lipopolysaccharide (LPS), LPS-binding protein (LBP), interleukin (IL)-1β and tumor necrosis factor (TNF)-α while downregulating IL-10. TLR9 activated the TARF3-TBK1-IRF3 signaling pathway. In vivo experiments showed HCQ reduced inflammation in FGR rats, and the relative cytokine expression followed a similar trend to that observed in vitro. TLR9 stimulated neutrophil activation. HCQ in FGR rats resulted in changes in the abundance of Eubacterium_coprostanoligenes_group at the family level and the abundance of Eubacterium_coprostanoligenes_group and Bacteroides at the genus level. TLR9 and associated inflammatory factors were correlated with Bacteroides, Prevotella, Streptococcus, and Prevotellaceae_Ga6A1_group. FMT from FGR rats interfered with the therapeutic effects of HCQ. In conclusion, our findings suggest that TLR9 regulates the inflammatory response and gut microbiota structure in FGR, providing new insights into the pathogenesis of FGR and suggesting potential therapeutic interventions.

Effects of Fetal Growth Restriction on Postnatal Gut Microbiota in a Rat Model.

Fetal growth restriction (FGR) indicates increased risks of lifestyle-related diseases in adulthood. Previous studies showed the association between human gut dysbiosis and various diseases. However, reports examining the relationship between FGR and gut microbiota are scarce. Herein, we hypothesized that FGR may cause gut dysbiosis and analyzed the gut microbiota in a FGR rat model by restricting maternal protein intake during pregnancy. The FGR group was developed by feeding pregnant Sprague Dawley rats a diet containing 7% protein until birth. Control rats were fed 21% protein. Fecal samples of 2-11-week-old pups were collected weekly. DNA was extracted from each sample and subjected to polymerase chain reaction (PCR) amplification and sequencing. Additionally, short-chain fatty acids in the cecum were analyzed at 2 weeks of age, when there were differences in the occupancy of the gut microbiota. Comparative analysis of the gut microbiota showed differences only at 2 weeks of age. Verrucomicrobia was significantly more abundant in the control group ( q < 0.1), whereas pathogenic bacteria, including Enterococcus and Enterobacteriaceae , tended to increase in the FGR group. The abundance of acetic and butyric acid-producing bacteria also differed between groups. Acetic acid in the cecum was considerably decreased in the FGR group, while butyric acid was increased compared to that in the control group. Normalizing the alteration of FGR on postnatal gut microbiota may have beneficial effects for the host, since the FGR group caused gut dysbiosis.

Fetal growth restriction followed by early catch-up growth impairs pancreatic islet morphology in male rats

Fetal growth restriction (FGR), followed by postnatal early catch-up growth, is associated with an increased risk of metabolic dysfunction, including type 2 diabetes in humans. This study aims to determine the effects of FGR and early catch-up growth after birth on the pathogenesis of type 2 diabetes, with particular attention to glucose tolerance, pancreatic islet morphology, and fibrosis, and to elucidate its mechanism using proteomics analysis. The FGR rat model was made by inducing mild intrauterine hypoperfusion using ameroid constrictors (ACs). On day 17 of pregnancy, ACs were affixed to the uterine and ovarian arteries bilaterally, causing a 20.9% reduction in birth weight compared to sham pups. On postnatal day 4 (P4), the pups were assigned to either the good nutrition (GN) groups with 5 pups per dam to ensure postnatal catch-up growth or poor nutrition groups with 15 pups per dam to maintain lower body weight. After weaning, all pups were fed regular chow food ad libitum (P21). Rats in both FGR groups developed glucose intolerance; however, male rats in the FGR good nutrition (FGR-GN) group also developed hypertriglyceridemia and dysmorphic pancreatic islets with fibrosis. A comprehensive and functional analysis of proteins expressed in the pancreas showed that FGR, followed by early catch-up growth, severely aggravated cell adhesion-related protein expression in male offspring. Thus, FGR and early catch-up growth caused pancreatic islet morphological abnormalities and fibrosis associated with the disturbance of cell adhesion-related protein expressions. These changes likely induce glucose intolerance and dyslipidemia in male rats.

Skeletal Muscle Insulin Resistance in a Novel Fetal Growth Restriction Model

The abnormal fetal environment exerts long-term effects on skeletal muscle, and fetal growth restriction (FGR) is associated with insulin resistance in adulthood. In this study, we examined insulin resistance in early adulthood and insulin signaling in skeletal muscle using a novel FGR rat model. Ameroid constrictors (AC) were placed on the bilateral uterine and ovarian arteries of rats on day 17 of gestation; placebo surgery was performed on the control group. We measured body weight at birth, 4, 8, and 12 weeks of age and performed oral glucose tolerance tests at 8 and 12 weeks. Rats were dissected at 12 weeks of age. We examined the mRNA and protein expression of insulin signaling pathway molecules in skeletal muscle. FGR rats had a significantly lower birth weight than control rats (p = 0.002). At 12 weeks of age, the incremental area under the curve of blood glucose was significantly higher, and GLUT4 mRNA and protein expression in soleus muscle was significantly lower in the FGR group than in the control group. Reduced placental blood flow in the AC-attached FGR group caused insulin resistance and altered insulin signaling in skeletal muscles. Therefore, FGR causes skeletal muscle insulin resistance in early adulthood.

The impact of maternal protein restriction during perinatal life on the response to a septic insult in adult rats.

Although abundant evidence exists that adverse events during pregnancy lead to chronic conditions, there is limited information on the impact of acute insults such as sepsis. This study tested the hypothesis that impaired fetal development leads to altered organ responses to a septic insult in both male and female adult offspring. Fetal growth restricted (FGR) rats were generated using a maternal protein-restricted diet. Male and female FGR and control diet rats were housed until 150-160 d of age when they were exposed either a saline (control) or a fecal slurry intraperitoneal (Sepsis) injection. After 6 h, livers and lungs were analyzed for inflammation and, additionally, the amounts and function of pulmonary surfactant were measured. The results showed increases in the steady-state mRNA levels of inflammatory cytokines in the liver in response to the septic insult in both males and females; these responses were not different between FGR and control diet groups. In the lungs, cytokines were not detectable in any of the experimental groups. A significant decrease in the relative amount of surfactant was observed in male FGR offspring, but this was not observed in control males or in female animals. Overall, it is concluded that FGR induced by maternal protein restriction does not impact liver and lung inflammatory response to sepsis in either male or female adult rats. An altered septic response in male FGR offspring with respect to surfactant may imply a contribution to lung dysfunction.

The effect of maternal protein restriction during perinatal life on the inflammatory response in pediatric rats.

Fetal growth restriction can affect health outcomes in postnatal life. This study tested the hypothesis that the response to an inflammatory pulmonary insult is altered in pediatric fetal growth restricted rats. Using a low-protein diet during gestation and postnatal life, growth-restricted male and female rats and healthy control rats were exposed to an inflammatory insult via the intratracheal instillation of heat-killed bacteria. After 6h, animal lungs were examined for lung inflammation and status of the surfactant system. The results showed that in response to an inflammatory insult, neutrophil infiltration was decreased in both male and female rats in the growth-restricted animals compared with the control rats. The amount of surfactant was increased in the growth-restricted animals compared with the control rats, regardless of the inflammatory insult. It is concluded that fetal growth restriction results in increased surfactant and altered neutrophil responses following pulmonary insult.

Dysregulated ion channels and transporters activate endoplasmic reticulum stress in rat kidney of fetal growth restriction

AimsThe mechanisms underlying the fetal origin of renal disease remains unknown. This study aimed to investigate the profiles of ion channel and transporter proteins in the fetal kidney in fetal growth restriction (FGR)rats, and to explore their association with the fetal origin of renal disease. Main methodsAn FGR rat model was developed by administration of a low-protein diet. Then 367 differentially expressed proteins (DEPs) from quantitative proteome analysis were subjected to Ingenuity Pathway Analysis. 22 DEPs associated with ion channels/transporters were evaluated in the fetal kidney. Na+/H+ exchanger1(NHE1) and its downstream unfolded protein response (UPR) pathway were investigated. Furthermore, overexpression of NHE1 were achieved via plasmid transfection to evaluate the potential influence on the UPR pathway and cell apoptosis in human proximal tubular epithelial cell line HK2 cells. Key findingsFindings were as follows: 1) In the FGR fetal kidney, aquaporin 2/4, solute carrier (SLC) 8a1, 33a1, etc. were downregulated, whereas other transporters including SLC 2a1, 4a1, 9a1, 29a3, etc. were upregulated. 2) NHE1 mRNA levels were markedly elevated in the FGR fetus. Further investigation revealed an increase in the UPR pathway regulators. 3) In vitro study showed that NHE1 overexpression in HK2 cells significantly induced expression of the endoplasmic reticulum stress (ERS) regulators and led to a decrease in the anti-apoptotic potential. SignificanceWe speculate that maternal protein malnutrition causes dysregulation of ion channels/transporters in the fetal kidney. Upregulated NHE1 may activate the UPR pathway and induce cell apoptosis thus leading to impairment of kidney function.

Establishment of a Novel Fetal Growth Restriction Model and Development of a Stem-Cell Therapy Using Umbilical Cord-Derived Mesenchymal Stromal Cells.

Fetal growth restriction (FGR) is a major complication of prenatal ischemic/hypoxic exposure and affects 5%–10% of pregnancies. It causes various disorders, including neurodevelopmental disabilities due to chronic hypoxia, circulatory failure, and malnutrition via the placenta, and there is no established treatment. Therefore, the development of treatments is an urgent task. We aimed to develop a new FGR rat model with a gradual restrictive load of uterus/placental blood flow and to evaluate the treatment effect of the administration of umbilical cord-derived mesenchymal stromal cells (UC-MSCs). To create the FGR rat model, we used ameroid constrictors that had titanium on the outer wall and were composed of C-shaped casein with a notch and center hole inside that gradually narrowed upon absorbing water. The ameroid constrictors were attached to bilateral ovarian/uterine arteries on the 17th day of pregnancy to induce chronic mild ischemia, which led to FGR with over 20% bodyweight reduction. After the intravenous administration of 1 × 105 UC-MSCs, we confirmed a significant improvement in the UC-MSC group in a negative geotaxis test at 1 week after birth and a rotarod treadmill test at 5 months old. In the immunobiological evaluation, the total number of neurons counted via the stereological counting method was significantly higher in the UC-MSC group than in the vehicle-treated group. These results indicate that the UC-MSCs exerted a treatment effect for neurological impairment in the FGR rats.

Dysregulation in the Unfolded Protein Response in the FGR Rat Pancreas.

Accumulating evidence suggests that fetal growth restriction (FGR) leads to the development of diabetes mellitus in adults. The aim of this study was to investigate the effect of protein malnutrition in utero on the pancreatic unfolded protein response (UPR) pathway in FGR offspring. An FGR model was developed by feeding a low-protein diet to pregnant rats throughout gestation. Eighty-four UPR pathway components in the pancreas were investigated by quantitative PCR arrays and confirmed by qPCR and western blotting. Activating transcription factor (Atf4 and Atf6), herpud1, protein kinase R-like endoplasmic reticulum kinase (Perk), X-box binding protein 1 (Xbp1), and the phosphorylation of eIF2α were upregulated, while cyclic AMP-responsive element-binding protein 3-like protein was markedly downregulated in FGR fetuses compared with controls. Investigation in adult offspring revealed temporal changes, for most UPR factors restored to normal, except that dysregulation of Atf6 and Creb3l3 maintained until adulthood. Moreover, autophagy was suppressed in FGR fetal pancreas and may be associated with decreased activation of AMP-activated protein kinase (Ampk). Apoptosis regulators Bax and cleaved-caspase 3 and 9 were upregulated in FGR fetal pancreas. Given that islet size and number were decreased in FGR fetus, we speculated that the aberrant intrauterine milieu impaired UPR signaling in fetal pancreas development. Whether these alterations early in life contribute to the predisposition of FGR fetuses to adult metabolic disorders invites further exploration.

Proteomics analysis of fetal growth restriction and taurine‑treated fetal growth restriction rat brain tissue by 2DDIGE and MALDI‑TOF/TOF MS analysis.

Fetal growth restriction (FGR) is caused by placental insufficiency and can lead to short and long-term neurodevelopmental delays. Taurine, one of the most abundant amino acids in the brain, is critical for the normal growth and development of the nervous system; however, the mechanistic role of taurine in neural growth and development remains unknown. The present study investigated the role of taurine in FGR. Specifically, we explored the proteomic profiles of fetal rats at 6 h postpartum by two-dimensional difference gel electrophoresis combined with matrix assisted laser desorption ionization-time-of-flight (TOF)/TOF tandem mass spectrometry; the findings were verified via reverse transcription-quantitative polymerase chain reaction. A total of 31 differentially expressed protein spots were selected. Among these, 31 were matched, including dihydropyrimidinase-related protein 2 and, CRK and peroxiredoxin 2. Functional analysis using the Gene Ontology database and Ingenuity Pathway Analysis demonstrated that the differentially expressed proteins were mainly associated with neuronal differentiation, 'metabolic process', 'biological regulation' and developmental processes. The present study identified several proteins that were differentially expressed in rats with FGR in the presence or absence of taurine administration. The results of the present study suggest a potential role for taurine in the treatment and prevention of FGR.

Prenatal Sildenafil Therapy Improves Cardiovascular Function in Fetal Growth Restricted Offspring of Dahl Salt-Sensitive Rats.

Fetal growth restriction (FGR) is associated with increased risk for cardiovascular and renal disorders in later life. Prenatal sildenafil improves birth weight in FGR animal models. Whether sildenafil treatment protects against long-term cardiovascular and renal disease in these offspring is unknown. The aim of this study is to test the hypothesis that prenatal sildenafil ameliorates cardiovascular and renal function in FGR offspring of Dahl salt-sensitive rats. Sildenafil citrate (60 mg/kg per day) or control gel diet (containing 0.3% salt) was administered from gestational day ten until birth. In male and female offspring, the mean arterial pressure was measured by telemetry in 1 subset from week 5 until week twenty. Echocardiographic parameters, glomerular filtration rate, and fractional electrolyte excretion were determined in another subset at week 9. Aortic and mesenteric artery rings were prepared to assess endothelial-dependent (acetylcholine) and -independent (sodium nitroprusside) vasorelaxation (week 10). The rise in mean arterial pressure per week was attenuated in treated versus untreated male offspring. Mesenteric arteries showed an increased endothelium-dependent relaxation and improved endothelium-independent relaxation in treated versus control male offspring. No differences in aortic relaxation, echocardiographic parameters or renal function were observed between groups. Prenatal sildenafil treatment subtly improves cardiovascular but not renal function in the offspring of this FGR rat model. Translationally, in utero treatment could be beneficial for cardiovascular programming in a sex-specific manner; however, caution is warranted since recent human trials have been halted because of potentially deleterious neonatal side effects when treating pregnancies complicated with severe FGR with sildenafil.

Trichloroethylene exposure in mid-pregnancy decreased fetal weight and increased placental markers of oxidative stress in rats

Although epidemiology studies have associated maternal trichloroethylene (TCE) exposure with decreased birth weight and preterm birth, mechanistic explanations for these associations are currently lacking. We hypothesized that TCE targets the placenta with adverse consequences for pregnancy outcomes. Pregnant Wistar rats were exposed orally to vehicle or 480 mg TCE/kg body weight from gestational days (gd) 6–16, and tissues were collected on gd 16. Exposure to TCE significantly decreased average fetal weight without reducing maternal weight. In placenta, TCE significantly increased 8-hydroxy-deoxyguanosine, global 5-hydroxymethylcytosine, and mRNA expression of Tet3, which codes for an enzyme involved in 5-hydroxymethylcytosine formation. Furthermore, glutathione S-transferase activity and immunohistochemical staining were increased in placentas of TCE-exposed rats. The present study provides the first evidence that TCE increases markers of oxidative stress in placenta in a fetal growth restriction rat model, providing new insight into the placenta as a potentially relevant target for TCE-induced adverse pregnancy outcomes.

Zinc improves learning and memory abilities of fetal growth restriction rats and promotes trophoblast cell invasion and migration via enhancing STAT3-MMP-2/9 axis activity.

Fetal growth restriction (FGR) is a well-known risk factor for cognitive dysfunction, especially for learning and memory abilities. However, knowledge about prevention and treatment methods of learning and memory abilities of fetal are limit. Here, Morris water maze and passive avoidance tests showed zinc supplementation could protect the impairment of the learning and memory abilities caused by FGR. As accumulating evidence suggested that insufficiency of placental trophoblast cell invasion was closely related to FGR fetal neurodevelopmental dysplasia, we further explored the relationship between zinc supplementation during pregnancy and placental trophoblast. Microarray identified 346 differently expressed genes in placental tissues with and without zinc supplementation, and GO and KEGG analyses showed these differently expressed genes were highly enriched in cell invasion and migration and STAT3 pathway. Protein-protein interaction(PPI) analysis found that STAT3 interacted with matrix metalloproteinase-2/9 (MMP-2/9). In vivo, western blot results authenticated that the expression levels of phospho-STAT3, STAT3, MMP-2 and MMP-9 were up-regulated in placental tissues after zinc treatment. To validate whether zinc could promotes trophoblast cell invasion and migration via enhancing STAT3-MMP-2/9 activity. In vitro, Transwell assay was performed, and we observed that abilities of invasion and migration were obviously increased in zinc treated trophoblast cells. And phospho-STAT3, STAT3, MMP-2 and MMP-9 expression levels were correspondingly increased in zinc treated trophoblast cells, which were dose-dependent. Moreover, gain–of-function and loss-of-function of STAT3 confirmed that zinc promotes cell invasion and migration via regulating STAT3 mediated up-regulation of MMP-2/9 activity. We propose that activation of MMP-2/9 mediated by STAT3 may contribute to invasion and migration of trophoblast cells, which improved neurodevelopmental impairment of FGR rats probably via contributing to placental development. Our findings are the first to show a possible mechanism of reversing neurodevelopmental impairment of FGR rats by zinc supplementation, holding promise for the development of novel therapeutic modalities for learning and memory abilities impairment caused by FGR.

Effect of vitamin D on the learning and memory ability of FGR rat and NMDA receptor expression in hippocampus.

The aim of this study is to investigate the effect of vitamin D (VD) on the learning and memory ability of fetal growth restriction (FGR) rat and the expression of NMDA receptor in hippocampus. The FGR models of rat were established through passive smoking, and divided into two groups randomly, i.e. the control group and the observation group. Rats were fed regular diet with the addition of VD in the observation group. The serum level of 25(OH)-D3 was assayed in both groups of the rats at different time points using ELISA, and the learning and memory ability of rat aged 30 days were evaluated using Morris water maze and passive avoidance test. In addition, we also compared the brain weight of rats at different age and detected the mRNA expression of NRI subunit of NMDA receptor of hippocampus of rats aged 30 days using quantitative RT-PCR. After 7 days, the serum level of 25(OH)D3 in rats of the observation group was significantly higher than that of the control group (P<0.05); during the Morris water maze, we found no significant difference in comparison of the latency between the two groups in the first 2 days (P>0.05), but from the 3rd day, the latency of the observation group was shorter than that in the control group (P<0.05); in the passive avoidance test, no significant difference was identified when comparing the electric shock times between the two groups in the first 2 days, but from the 3rd day, the electric shock times in the observation group were significantly lower than those in the control group (P<0.05); the brain weight of rats in the observation group on the 1st, 7th and 14th day were all lower than those in the control group (P<0.05), but the comparison of brain weight at 21st and 30th day showed no significant difference (P>0.05) between the two groups. We also found that the mRNA and protein expression of NRI subunit of NMDA receptor in hippocampus was significantly higher in the observation group than in the control group (P<0.05). VD can increase the learning and memory ability of FGR rats, significantly ameliorating the cognitive dysfunction of FGR rat and improving the learning and memory ability of rats, which may be related to the upregulation of NRI subunit of NMDA receptor.

Assessment of body composition in Wistar rat offspring by DXA in relation to prenatal and postnatal nutritional manipulation.

This experimental study aims to investigate the impact of combinations of prenatal and postnatal food manipulation on body composition in rat offspring. On day 12 of gestation, 100 timed pregnant rats were randomized into two nutritional groups: standard laboratory and 50% starved. Pups born to starved mothers were subdivided, based on birthweight (BiW), into fetal growth restricted (FGR) and non-FGR. Pups were born on day 21, cross-fostered, then left undisturbed lactating until the 26th postnatal day when they underwent dual-energy X-ray absorptiometry (DXA) examination. Prenatally control-fed animals had a significantly greater body weight at 26 d postnatally than the prenatally starved groups, irrespective of their postnatal diet (P < 0.001). Postnatal control diet was associated with significantly increased abdominal and total fat in non-FGR compared to FGR rats (P < 0.001). non-FGR/CONTROL rats showed higher values of abdominal fat than prenatally starved animals that were starved postnatally irrespective of their birth weight (P < 0.001). Postnatal control diet significantly increased total bone mineral content (BMC), head BMC, head area, abdominal BMC in non-FGR compared to FGR rats (P < 0.001). Interaction between prenatal and postnatal nutrition affects growth, abdominal adiposity, and bone accrual in Wistar rats' offspring at 26 d of life.

Effects of folic acid and vitamin B12 on insulin resistance of fetal growth restriction 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). 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). 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). 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 (1.0±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. Key words: Fetal growth retardation; Insulin resistance; Folic acid; Vitamin B12; Rats, Sprague-Dawley

Expression of lung surfactant proteins SP-B and SP-C and their modulating factors in fetal lung of FGR rats.

This study investigated the expression of lung surfactant proteins SP-B and SP-C, and their modulating factors TTF-1 and PLAGL2 in the fetal lung of rats with fetal growth restriction (FGR). The rat FGR model was established by prenatal hypoxia in the first stage of pregnancy, 180 rats for experiment served as hypoxia group, and 197 healthy rats served as normal control group. The FGR incidence in hypoxia was compared with that in normal control group. The histological changes in the fetal lung were observed under the light microscope and electronic microscope in two groups. The SP-B, SP-C, TTF-1 and PLAGL2 proteins were determined in the fetal lung of two groups immunohistochemically. The expression levels of SP-B, SP-C, TTF-1 and PLAGL2 protein and mRNA in the fetal lung of two groups were detected by using Western blotting and RT-PCR respectively. The FGR rat model was successfully established by using hypoxia. Pathologically the fetal lung developed slowly, and the expression levels of SP-B, SP-C, TTF-1 and PLAGL2 protein and mRNA in the fetal lung were significantly reduced in hypoxia group as compared with those in normal control group. It was suggested that maternal hypoxia in the first stage of pregnancy could induce FGR, and reduce the expression of SP-B and SP-C, resulting in the disorder of fetal lung development and maturation.

Expression of soluble vascular endothelial growth factor receptor-1 and placental growth factor in fetal growth restriction cases and intervention effect of tetramethylpyrazine

ObjectiveTo investigate the expression of soluble vascular endothelial growth factor receptor-1 (sFlt-1) and placental growth factor (PLGF) in the fetal growth restriction (FGR) cases and the intervention mechanism of tetramethylpyrazine. MethodsA total of 60 fetal growth restriction cases that admitted to our hospital were randomly divided into ligustrazine intervention group (group A) and nutritional support group (group B). A total of 50 healthy pregnant women were also enrolled as control group (group C). Expression level of maternal serum sFlt1, PLGF and fetal growth parameters including HC, AC, FL, BPD, EFW as well as placenta PLGF, sFlt-1 mRNA expression were recorded and compared among the three groups. A total of 15 SD rats were selected and were divided into three groups, TMP group, alcohol and tobacco group and blank control group. Three groups of rats were dissected on the twentieth day of gestation. ResultsExpression level of sFlt-1 and PLGF in group A was not significantly different from that of group C (P>0.05); but significant difference in SFlt1 and PLGF expression level was observed between group C and group B (P<0.05). Before treatment, HC, AC, FL, BPD and EFW of group A and group B were significant lower than those of group C, but after treatment, those parameters in group A were significantly improved (P<0.05). In the animal experiment there was no significant difference in sFlt-1 between treatment group and FGR group without treatment or control group (P>0.05). There was significant difference in PLGF between FGR group with treatment and FGR group without treatment or control group (P<0.01). ConclusionsPLGF level is decreased and sFlt-1 increased in patients suffered from fetal growth restriction, and FGR rats show increased sFlt-1 and decreased PLGF, thus they can be indicator of the fetal growth restriction. Ligustrazine can effectively improve sFlt-1, PLGF expression level in fetal growth restriction cases, which can be used as treatment for FGR.