Preterm Rats Research Articles

Detection of Matrix Metalloproteinases in the Heart of Preterm Rats

Detection of Matrix Metalloproteinases in the Heart of Preterm Rats

Changes in intestinal microflora and its metabolites underlie the cognitive impairment in preterm rats.

BackgroundThe brain development of preterm infants is easily affected by various adverse extrauterine factors and complications, resulting in abnormal neurological and cognitive development. Recent studies have found that there is a significant correlation between intestinal microbial changes and cognitive behavior. Nevertheless, the correlation between the cognitive impairment and abnormal changes of intestinal microflora in the preterm newborn has been rarely elucidated.AimTo analyze the differences of fecal intestinal flora, short chain fatty acids (SCFAs) and microbiota-gut-brain axis (MGBA)-related serum factors between preterm birth with and without cognitive impairment.MethodsHealthy female rats (body weight 410 ± 40 g) of 16-17 days of gestation were selected for the establishment of preterm cognitive impairment model and screened by Morris water maze navigation experiments. The pathological change of rat hippocampus was confirmed by HE staining. The abundance of fecal intestinal microflora was determined by 16sRNA sequencing, while the contents of fecal SCFAs were examined by gas chromatography.ResultsCompared with the control group, the cognitive impairment group had decreased abundance and diversity of intestinal microflora and increased abundance of Proteobacteria at the level of phylum. While the abundances of Alistipes, Bacteroides, Prevotella, and Lactobacillus decreased significantly at the level of order, family, and genus, the abundances of Staphylococcaceae, Enterococci, Psychrobacter, and Oligella increased significantly. Moreover, the levels of total SCFAs and acetic acid in the disease group were significantly lower. The fecal abundance of acetic acid was positively correlated with that of Lactobacillaceae or Peptostreptococcaceae, and negatively correlated with that of Aerococcaceae, and Alcaligenaceae in disease rats. Furthermore, cognitive impairment caused significantly decreased levels of 5-HT, GABA, and BDNF, and increased levels of GR, CRH, IL-6, and TNF-α in rat blood.ConclusionAlterations in intestinal microflora structure and the abundances of SCFAs contributed substantially to the cognitive impairment in preterm rats, which was associated with significant changes in MGBA-related soluble factors.

PARP-1 Inhibition Repressed Imbalance of Th17 and Treg Cells in Preterm Rats with Intrauterine Infection-Induced Acute Respiratory Distress Syndrome by Reducing the Expression Level of IL-6.

Background Abundant reports have uncovered an imbalance of Treg and Th17 cells in pulmonary diseases. Hereon, we intend to explore the impact of PARP-1 on the imbalance of Th17/Treg and the potential mechanism in premature rats with acute respiratory distress syndrome (ARDS). Methods Preterm ARDS infants and healthy term infants were enrolled in this investigation. To induce a rat model of ARDS, E.coli suspension was given to rats through two vaginal dilator-guided intramuscular injections. H&E staining was used to perform histopathological examination. Flow cytometry was employed to assess the proportion of Th17 or Treg cells accounted for CD4+ T cells. ELISA was applied to measure levels of IL-6, IL-17A, and IL-10 in the serum of ARDS patients. Moreover, the mRNA and protein expression levels of PARP-1, IL-6, IL-17A, and IL-10 were detected through qRT-PCR and western blotting. Results An increased Th17/Treg ratio was observed in preterm infants and rats with ARDS. The PARP-1 expression level was raised in the lung tissues of ARDS rats, and PARP-1 downregulation alleviated E.coli-induced lung injury in preterm rats. Expression levels of PARP-1, IL-6, and IL-17A were raised, and the IL-10 level was reduced in the lung tissues of rats after E.coli treatment, which was all reversed by PARP-1 suppression. Importantly, the ratio of Th17/Treg differentiated from purified CD4+ T cells of the E.coli + PARP-1 inhibitor group was elevated by recombinant IL-6. Conclusion PARP-1 downregulation repressed the imbalance of Th17 and Treg cells via reducing the expression level of IL-6, implying that PARP-1 may be a promising target for ARDS therapy.

Increasing urinary podocyte mRNA excretion and progressive podocyte loss in kidney contribute to the high risk of long-term renal disease caused by preterm birth

Podocyte abnormalities are common mechanism driving the progression of glomerular diseases, which account for most chronic kidney diseases (CKDs). However, the role of podocyte in the mechanism of high-risk long-term CKD caused by prematurity has not been well clarified. In present study, urine samples of 86 preterm infants and 32 full-term infants were collected, and podocyte-specific podocin mRNA levels in urine pellet were applied to indicate urinary podocyte mRNA excretion. In addition, in a preterm animal rat model, preterm rats were identified by delivery 2 days early. From the age of 3 weeks–12 months, urine samples were collected to examine podocyte mRNA excretion by measuring podocyte-specific podocin mRNA levels. Kidney samples at the age of 3 weeks, 2 months, and 12 months were collected from 8, 5 and 6 preterm rats and 9, 6 and 8 full-term rats, respectively, to examine podocyte density and podocyte area by measuring the podocyte specific nuclear marker WT-1 and the podocyte specific marker synaptopodin. As results, a more than threefold increase of urinary podocyte-specific podocin mRNA excretion rate was found in preterm infants compared with full-term infants. In addition, there was negative correlation between gestational age at birth and urinary podocin mRNA excretion. In preterm rats, a reduction in the total number of differentiated podocytes in glomeruli and an increased podocyte podocin mRNA excretion rate in urine were detected at the end of kidney differentiation. Moreover, long-term follow-up data in preterm rats showed there was an increased the risk of renal disease indicated by persistent podocyte mRNA loss, proteinuria, and enlarged glomeruli. In conclusion, increasing podocyte mRNA excretion in urine and podocyte loss in kidney led by prematurity drive the progression of long-term abnormal kidney function and could potentially explain the high risk of long-term CKD in preterm infants.

Possible antiapoptotic and neuroprotective effects of magnesium sulphate on retina in a preterm hypoxic-ischemic rat model

Background/aim The effects of systemic magnesium sulfate (MgSO4) on retina in preterm hypoxic-ischemic (HI) rat model are not known. Our aim was to investigate the effects of MgSO4 on retinal ganglion cell (RGC) count, retinal ganglion cell (RGC) apoptotic index, retinal vascular endothelial growth factor receptor-2 (VEGFR-2), and glial fibrillary acidic protein (GFAP) expressions in preterm HI rat model.Materials and methods Fifteen, postnatal day (PND) 7 rat pups were divided into 3 groups: 1. Sham-operated group, 2. HI group, and 3. MgSO4-treated HI group. The second and third groups underwent ischemia followed by exposure to hypoxia for 2 h (Vannucci model). The first and second groups received intraperitoneal saline and the third group received intraperitoneal MgSO4. On PND 10, eyes of the pups were evaluated for RGC count, apoptotic index, VEGFR-2, and GFAP expressions. Results In both HI and MgSO4-treated HI group, the mean total RGC counts were found to be significantly decreased. However, the mean total RGC count in the MgSO4-treated HI group was significantly higher than that of the HI group. The mean apoptotic index was found to be significantly increased in the HI group. Retinal VEGFR-2 and GFAP expressions were found to be significantly higher in the HI group.ConclusionsMagnesium sulfate preconditioning andtreatment in preterm HI rat model might diminish apoptosis, relatively preserve RGCs, and reduce retinal VEGFR-2 and GFAP expressions.

P0639 / #1836: PROBIOTICS FOR TREATMENT OF NECROTIZING ENTEROCOLITIS IN A MURINE MODEL

Aims & Objectives: Necrotizing enterocolitis (NEC) is one of the devastating gastrointestinal disorders. Probiotics are believed to decrease the risk of NEC and it has also been used for its treatment Methods: A total of 142 Sprague-Dawley (SD) rats were used to secure a total of 80 neonatal pubs. NEC was induced through exposing neonatal rats obtained via caesarean section after 18-20 days gestation (prematurity stage) to asphyxia and cold stress. Pubs were randomly divided into the following four groups: Group I (n=20) were hypoxia formula feeding (FFH) rat model of induced NEC, who have no therapy. Group II (n=20) included 20 rats of FFH-rat model of induced NEC, who underwent probiotic treatment. Group III (n=20) were rat models FFH-rat model of induced NEC, treated by oral antibiotics. Group IV (n=20) included premature, breast-fed rats, serving as controls. Seven days after birth, all rats were sacrificed, intestinal injury and TNF-α-, IL-18-, as well as iNOS2-expression in the intestine and liver were assessed. Results: Probiotics reduced the histological score and thus significantly reduced the rate of NEC-like intestinal injury. NEC was associated with increased Hepatic TNF-α and IL-18 positive cells. Moreover, the intestinal flushes level of TNF-α in NEC rats were increased in correlation to the controls. This high level of intestinal TNF-α and the other inflammatory liver parameters were significantly decreased in the probiotics treated model. Conclusions: This experimental study demonstrated that probiotics could treat NEC in preterm neonatal rats. The mechanism for this action might be associated with the suppressed expression of pro inflammatory mediators.

461 Magnesium sulphate (Mg) doses for neuroprotection: low is better

Antenatal magnesium sulphate (Mg) is recommended for neuroprotection associated with preterm birth. However, the exact dose and duration, are still under debate. The ACOG recommends to use one of three protocols with a total Mg supplementation of 4 (loading only) to 31.5grams (loading+maintenance). Recent studies imply that while low dose Mg may help neuronal survival, higher doses may promote cell apoptosis. In clinical trials preterm neonates with high MG had increase morbidity and mortality. In the present study we sought to investigate the optimal dosing of Mg in a preterm rat model. Pregnant rats at 20d of gestation (30 total, N = 5) received i.p. LPS (500 μg/kg) or saline. Dams were randomized to s.c. saline, Low Mg-loading dose of 150mg/kg and High Mg-loading dose (150 mg/kg) +maintenance (15mg/kg q20 min for 2h prior to and following the i.p. injections). Dams were sacrificed 4h following the first injection. Fetal brains were analyzed for inflammatory cytokines (western blot). Maternal and fetal serum Mg levels and inflammatory cytokines were analyzed and compared between groups (ELISA). Maternal and fetal serum Mg levels were lowest in the SAL groups, increased in Low Mg group and were highest in the High Mg groups. Fetal brain IL-6 and TNF-α protein levels increased in the LPS/SAL compared to SAL/SAL groups (IL-6 2.06+0.05 VS 0.75+0.12U, TNF-α 2.11+0.04 vs 0.76+0.12U). Maternal Mg administration reduced fetal brain inflammatory cytokines following LPS compared to LPS/SAL group to basal levels (IL-6 0.71+0.04 vs 2.06+0.05 U, TNF-α 0.75+0.13U) for LPS/Low Mg and (IL-6 0.73±0.26 VS 2.06+0.05U, TNF-α 0.74+0.33 vs 2.11+0.04U for LPS/High Mg respectively, p<0.05). Similar pattern was demonstrated in maternal and fetal serum. Fetal serum Mg levels increase in direct proportion to maternal Mg dose. Low Mg was as effective as High Mg in reducing inflammatory markers. Our results imply that loading dose regime is effective in preventing neuroinflammation and may prevent long term sequela potentially associated with high fetal Mg levels.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Prenatal glucocorticoid administration accelerates glomeruli and renal tubules development in the fetal rats.

Prenatal glucocorticoid (GC) administration has shown to develop the pulmonary circulation in the neonate. However, the effects of the kidney functions remains unknown. This study aimed to investigate whether prenatal GC administration is associated with fetal kidney development in the preterm model rats.

A Model of Germinal Matrix Hemorrhage in Preterm Rat Pups.

Germinal matrix hemorrhage (GMH) is a serious complication in extremely preterm infants associated with neurological deficits and mortality. The purpose of the present study was to develop and characterize a grade III and IV GMH model in postnatal day 5 (P5) rats, the equivalent of preterm human brain maturation. P5 Wistar rats were exposed to unilateral GMH through intracranial injection into the striatum close to the germinal matrix with 0.1, 0.2, or 0.3 U of collagenase VII. During 10 days following GMH induction, motor functions and body weight were assessed and brain tissue collected at P16. Animals were tested for anxiety, motor coordination and motor asymmetry on P22–26 and P36–40. Using immunohistochemical staining and neuropathological scoring we found that a collagenase dose of 0.3 U induced GMH. Neuropathological assessment revealed that the brain injury in the collagenase group was characterized by dilation of the ipsilateral ventricle combined with mild to severe cellular necrosis as well as mild to moderate atrophy at the levels of striatum and subcortical white matter, and to a lesser extent, hippocampus and cortex. Within 0.5 h post-collagenase injection there was clear bleeding at the site of injury, with progressive increase in iron and infiltration of neutrophils in the first 24 h, together with focal microglia activation. By P16, blood was no longer observed, although significant gray and white matter brain infarction persisted. Astrogliosis was also detected at this time-point. Animals exposed to GMH performed worse than controls in the negative geotaxis test and also opened their eyes with latency compared to control animals. At P40, GMH rats spent more time in the center of open field box and moved at higher speed compared to the controls, and continued to show ipsilateral injury in striatum and subcortical white matter. We have established a P5 rat model of collagenase-induced GMH for the study of preterm brain injury. Our results show that P5 rat pups exposed to GMH develop moderate brain injury affecting both gray and white matter associated with delayed eye opening and abnormal motor functions. These animals develop hyperactivity and show reduced anxiety in the juvenile stage.

Expression of ubiquitin-specific protease 7 in lung tissue of preterm rats after hyperoxia exposure

Objective To study the expression and significance of ubiquitin-specific protease 7 (USP7) and the key factors of the Wnt signaling pathway in the lung tissue of preterm rats after hyperoxia exposure. Methods A total of 180 preterm neonatal Wistar rats were randomly divided into an air control group, an air intervention group, a hyperoxia control group, and a hyperoxia intervention group, with 45 rats in each group. Lung injury was induced by hyperoxia exposure in the hyperoxia groups. The preterm rats in the intervention groups were given intraperitoneal injection of the USP7 specific inhibitor P5091 (5 mg/kg) every day. The animals were sacrificed on days 3, 5, and 9 of the experiment to collect lung tissue specimens. Hematoxylin-eosin staining was used to observe the pathological changes of lung tissue. RT-PCR and Western blot were used to measure the mRNA and protein expression levels of USP7 and the key factors of the Wnt signaling pathway β-catenin and α-smooth muscle actin (α-SMA) in lung tissue. Results The air groups had normal morphology and structure of lung tissue; on days 3 and 5, the hyperoxia control group showed obvious alveolar compression and disordered structure, with obvious inflammatory cells, erythrocyte diapedesis, and interstitial edema. On day 9, the hyperoxia control group showed alveolar structural disorder and obvious thickening of the alveolar septa. Compared with the hyperoxia control group at the corresponding time points, the hyperoxia intervention group had significantly alleviated disordered structure, inflammatory cell infiltration, and bleeding in lung tissue. At each time point, the hyperoxia groups had a significantly lower radial alveolar count (RAC) than the corresponding air groups (P 0.05). There were no significant differences in the mRNA expression of USP7 and β-catenin and the protein expression of USP7, β-catenin, and α-SMA between the air intervention and air control groups (P > 0.05). Conclusions Hyperoxia exposure can activate the Wnt/β-catenin signaling pathway, and USP7 may participate in hyperoxic lung injury through the Wnt/β-catenin signaling pathway. The USP7 specific inhibitor P5091 may accelerate the degradation of β-catenin by enhancing its ubiquitination, reduce lung epithelial-mesenchymal transition, and thus exert a certain protective effect against hyperoxic lung injury.

Immunohistochemical analysis of protective effects of maternal fingolimod on the placenta and fetal lung and brain in chorioamnionitis-induced preterm birth rat model

Objectives Fingolimod (FIN) is used for multiple sclerosis treatment and has potential antiapoptotic and anti-inflammatory effects. We aimed at expanding our knowledge on various immunohistochemical markers for elucidating the possible mechanisms of action of fingolimod in the placenta and fetal lung and brain. Methods Sixteen pregnant rats were divided into four groups. On gestational day 17, lipopolysaccharide (LPS) was injected intraperitoneally to induce preterm fetal injury followed by intraperitoneal injection of fingolimod. Hysterotomy for preterm delivery was performed 6 h after fingolimod was injected. The study groups included (1) control, (2) LPS (1 mg/kg), (3) FIN (4 mg/kg), and (4) FIN + LPS. Fetal brain and lung and placenta samples were collected for histopathological examination. Moreover, fetal lungs (surfactant protein-A (SP-A), SP-B, SP-D, caspase-3, and caspase-8), fetal brains (interleukin-10, interleukin-1β, TNF-α, caspase-8, glial fibrillary acidic protein, vimentin, myelin basic protein, and receptor activator of nuclear factor kappa), and placenta tissues (interleukin-10, interleukin-1β, TNF-α, caspase-3, and caspase-8) were immunohistochemically evaluated. Results Maternal fingolimod treatment led to attenuation of LPS-induced fetal brain, lung, and placental injury, as indicated by lower immunoexpression of inflammatory markers compared to LPS group (p < .0001 for all comparisons). Conclusion The findings of the present study confirm the neuroprotective effects of antenatally administered fingolimod, which also significantly improved preterm fetal lung injury and placental inflammation in LPS-exposed preterm pregnancies by possible antiapoptotic and anti-inflammatory effects.

Role of Tissue-Type Plasminogen Activator in Remodeling of the Ductus Arteriosus

Vascular remodeling (e.g., intimal thickening) is necessary for complete closure of the ductus arteriosus (DA). Smooth muscle cells are reported to contribute to DA remodeling. In contrast, the contribution of endothelial cells remains largely unknown. Recent data showed that tissue-type plasminogen activator (t-PA) was highly expressed in the endothelial cells of rat and human DA. It is well known that t-PA is an activator of the blood fibrinolytic system, but t-PA-induced localized proteolysis has been reported to play an important role in vascular development. We found that t-PA-induced plasminogen-plasmin conversion promoted matrix metalloproteinase-2 activation in endothelial cells of rat DA. Gelatinase activity was noted at the internal elastic laminae (IEL) of rat and human DA on in situ gelatin zymography. The in vivo injection of plasminogen to pre-term rats increased gelatinase activation, IEL disruption, and the subsequent intimal thickening formation in the pre-term rat DA. Human DA results partly supported the rat DA findings, suggesting that t-PA-mediated DA remodeling may also be present in the human DA. Current pharmacotherapy for patent DA (PDA) mainly focuses on increasing vascular constriction. Elucidating the molecular mechanisms of DA remodeling may help to expand the range of therapeutic strategies for PDA.

Effects of hyperoxia exposure on the expression of Nrf2 and heme oxygenase-1 in lung tissues of premature rats

Bronchopulmonary dysplasia (BPD) is a chronic lung disease with long-term sequelae including neurodevelopmental delay. Although the precise mechanism of BPD is not well defined, oxidative stress is thought to be involved in the pathogenesis process of BPD. Nrf2 (Nuclear factor erythroid 2-related factor 2)-Keap1 (Kelch-like ECH associated protein 1)-ARE (Antioxidant Reaction Elements) signaling pathway is one of the main protective mechanisms of BPD, which can induce cytoprotective gene expression, such as heme oxygenase‐1 (HO-1), nicotinamide quinone oxidoreductase 1 (NQO1) and so on. We exposed premature rats to hyperoxia and identified lung developmental retardation in preterm rats, with similar pathological changes as BPD. The expression of Nrf2 and HO-1 in premature rats was significantly higher after hyperoxia exposure. To explore the changes of Nrf2 and HO-1 in premature rats and enhance their beneficial functions may provide new treatment strategies for infants at risk of BPD.

P.202 Pre and post insult treatment with cannabidiol prevents intraventricular hemorrhage-induced brain damage in preterm rats

P.202 Pre and post insult treatment with cannabidiol prevents intraventricular hemorrhage-induced brain damage in preterm rats

Leptin and EGF Supplementation Enhance the Immune System Maturation in Preterm Suckling Rats.

In preterm newborns the immaturity of the immune system is remarkable, with reduced innate and adaptive immune responses. Many bioactive compounds in breast milk, such as growth factors and adipokines, contribute to the immune system’s maturation in early life. However, studies on the immunoregulatory activity in preterm neonates are practically nonexistent. The aim of the present study was to determine whether a nutritional supplementation in early life with leptin or epidermal growth factor (EGF) was able to promote the maturation of the systemic and intestinal immune system in preterm conditions. For this purpose, premature rats were daily supplemented by oral gavage with leptin or EGF. Term and Preterm groups receiving vehicle were used as controls. Preterm rats showed deficiencies compared to full-term ones, such as lower body weights, erythrocyte counts, plasma IgG and IgM concentrations and B cell percentages, and higher values of Th and Tc TCRαβ+ cells in mesenteric lymph nodes, and intestinal permeability, among others. However, leptin and EGF supplementation were able to revert some of these deficiencies and to improve the premature immune system’s development. These results suggest that leptin and EGF are involved in enhancing the maturation of the systemic and intestinal immune system in preterm conditions.

Peptidomic analysis of hippocampal tissue for explore leptin neuroprotective effect on the preterm ischemia-hypoxia brain damage model rats

The most common injury of preterm infants is periventricular leukomalacia (PVL) and to date there is still no safe and effective treatment. In our previous studies, leptin has been found to have neuroprotective effects on the preterm ischemia-hypoxia brain damage model rats in animal behavior. To gain insight into the neuroprotective mechanisms of leptin on preterm brain damage model rats, we constructed a comparative peptidomic profiling of hippocampal tissue between leptin-treated after model and preterm ischemia-hypoxia brain damage model rats using a stable isobaric labeling strategy involving tandem mass tag reagents, followed by nano liquid chromatography tandem mass spectrometry. We identified and quantified 4164 peptides, 238 of which were differential expressed in hippocampal tissue in the two groups. A total of 150 peptides were up regulated and 88 peptides were down regulated. These peptides were imported into the Ingenuity Pathway Analysis (IPA) and identified putative roles in nervous system development, function and diseases. We concluded that the preterm ischemia-hypoxia brain damage model with leptin treatment induced peptides changes in hippocampus, and these peptides, especially for the peptides associated “microtubule-associated protein 1b (MAP1b), Elastin (Eln), Piccolo presynaptic cytomatrix protein (Pclo), Zinc finger homeobox 3(Zfhx3), Alpha-kinase 3(Alpk3) and Myosin XVA(Myo15a) ”, could be candidate bio-active peptides and participate in neuroprotection of leptin. These may advance our current understanding of the mechanism of leptin's neuroprotective effect on preterm brain damage and may be involved in the etiology of preterm brain damage. Meanwhile, we found that repression of ILK signaling pathway plays a significant role in neuroprotection of leptin. A better understanding of the role of ILK signaling pathway in neuroprotective mechanisms will help scientists and researchers to develop selective, safe and efficacious drug for therapy against human nervous system disorders.

Effect of intermittent hypoxia or hyperoxia on lung development in preterm rat neonates during constant oxygen therapy.

Impaired lung development is a major negative factor in the survival of preterm neonates. The present study was aimed to investigate the impact of constant oxygen, intermittent hyperoxia, and hypoxia on the lung development in preterm rat neonates. Neonatal rats were exposed to 40% O2 with or without brief hyperoxia episodes (95% O2 ) or brief hypoxia episodes (10% O2 ) from day 0 to day 14, or to room air. The body weight, radical alveolar count (RAC), and total antioxidant capacity (TAOC) were significantly lower whereas the lung coefficient and malondialdehyde (MDA) were significantly higher in the hyperoxia and hypoxia groups than the air control and constant oxygen group at day 7, day 14, and day 21 after birth. The lung function indexes were reduced by intermittent hyperoxia and hypoxia. In contrast, the constant oxygen therapy increased the lung function. HIF-1α and VEGF expression were significantly increased by hypoxia and decreased by hyperoxia. The constant oxygen therapy only decreased the HIF-1α expression at day 14 and 21. In summary, the constant oxygen treatment promoted lung function without affecting the antioxidative capacity in preterm rat neonates. While intermittent hyperoxia and hypoxia inhibited lung development, decreased antioxidative capacity, and dysregulated HIF-1α/VEGF signaling in preterm rat neonates.

A Preterm Rat Model for Immunonutritional Studies.

Neonates are born with an immature immune system, which develops during the first stages of life. This early immaturity is more acute in preterm newborns. The aim of the present study was to set up a preterm rat model, in which representative biomarkers of innate and adaptive immunity maturation that could be promoted by certain dietary interventions are established. Throughout the study, the body weight was registered. To evaluate the functionality of the intestinal epithelial barrier, in vivo permeability to dextrans was measured and a histomorphometric study was performed. Furthermore, the blood cell count, phagocytic activity of blood leukocytes and plasmatic immunoglobulins (Ig) were determined. Preterm rats showed lower erythrocyte and platelet concentration but a higher count of leukocytes than the term rats. Although there were no changes in the granulocytes’ ability to phagocytize, preterm monocytes had lower phagocytic activity. Moreover, lower plasma IgG and IgM concentrations were detected in preterm rats compared to full-term rats, without affecting IgA. Finally, the intestinal study revealed lower permeability in preterm rats and reduced goblet cell size. Here, we characterized a premature rat model, with differential immune system biomarkers, as a useful tool for immunonutritional studies aimed at boosting the development of the immune system.

Systemic multipotent adult progenitor cells improve long-term neurodevelopmental outcomes after preterm hypoxic-ischemic encephalopathy

There is an urgent need for therapies that could reduce the disease burden of preterm hypoxic-ischemic encephalopathy. Here, we evaluate the long-term effects of multipotent adult progenitor cells (MAPC) on long-term behavioral outcomes in a preterm rat model of perinatal asphyxia. Rats of both sexes were treated with two doses of MAPCs within 24 h after the insult. Locomotor, cognitive and psychiatric impairments were evaluated starting at 1.5 (juvenile) and 6 months (adult). Hypoxia-ischemia affected locomotion, cognition, and anxiety in a sex-dependent manner, with higher vulnerability observed in males. The MAPC therapy partially attenuated deficits in object recognition memory in females of all tested ages, and in the adult males. The hypoxic insult caused delayed hyperactivity in adult males, which was corrected by MAPC therapy. These results suggest that MAPCs may have long-term benefits for neurodevelopmental outcome after preterm birth and global hypoxia-ischemia, which warrants further preclinical exploration.

Intrauterine Inflammation Damages Placental Angiogenesis via Wnt5a-Flt1 Activation.

Intrauterine inflammation is the main reason for neonatal adverse outcomes and normal placenta perfusion plays an important role in fetal development. However, whether inflammation will affect placental angiogenesis and the underlying mechanism are still poorly understood. To investigate lipopolysaccharide (LPS)-induced intrauterine inflammation on placenta angiogenesis and Wnt5a-Flt1 expression. LPS-induced intrauterine inflammation rat model was established. Preterm rat outcomes were analyzed and angiogenesis of placenta villi was calculated by immunohistochemistry (IHC) of CD34 staining, and placenta Wnt5a-Flt1 expression was detected by western blot and IHC. Compared to control group, neonatal rats in LPS group showed higher death rate (1.4% vs 10.1%, p< 0.05) and lower birth weight (6.36 ± 0.48 vs 5.70 ± 0.67, p< 0.01); the villi vessel area and mean diameter in the placenta were significantly reduced in the LPS group (total area %, 16.7% ± 0.6% vs 8.7% ± 0.4%, p< 0.01, n= 9; mean diameter (pixel), 15.6 ± 0.5 vs 12.9 ± 0.3, p< 0.01, n= 9). Placenta Wnt5a-Flt1 expression was upregulated significantly (integrated optical density (IOD) in IHC: Wnt5a, 1667 ± 1204 vs 11,076 ± 4046, p< 0.05; Flt1, 2554 ± 466.2 vs 7998 ± 1613, p< 0.05; western blot: Wnt5a, 0.33 ± 0.05 vs 0.96 ± 0.06, p< 0.05; Flt1, 0.36 ± 0.15 vs 1.08 ± 0.08, p< 0.05). Intrauterine inflammation gave rise to offspring death rate and low birth weight; the mechanism might be disordered placental angiogenesis via Wnt5a-Flt1 activation triggered by inflammation.