Early administration of xenon-oxygen mixture in neonatal hypoxic-ischemic encephalopathy

Hyperoxia plays a significant role in the pathogenesis of lung injury, such as bronchopulmonary dysplasia (BPD), in premature infants or newborns. BPD management aims to minimize further injury, provide an optimal environment to support growth and recovery. In clinic neonatal care, we need a new therapy for BPD. Heat shock protein 70 (Hsp70) inhibit cell apoptosis and promote cell repair allowing cells to survive lethal injury. We hypothesized that Hsp70 could be used to prevent hyperoxia related BPD in the neonatal rat model through its anti-apoptotic and anti-inflammatory effects. In this study, we explored the effect of Hsp70 on hyperoxia-induced lung injury using neonatal rats. Neonatal Wistar rats were delivered naturally at full term of gestation and were then pooled and randomly assigned to several groups to receive heat stimulation (41°C for 20 min) or room temperature conditions. The Hsp70 group received recombinant Hsp70 intraperitoneally (200 μg/kg, daily). All newborn rats were placed under hyperoxic conditions (85% oxygen) for 21 days. Survival rates in both heat-hyperoxia and Hsp70-hyperoxia groups were higher than those in the hyperoxia group (p < 0.05). Both endogenous and exogenous Hsp70 could reduce early apoptosis of alveolar cells under hyperoxia. Additionally, there were less macrophage infiltration in the lung of the Hsp70 groups (p < 0.05). Heat stress, heat shock proteins, and exogenous recombinant Hsp70 significantly increased the survival rate and reduced pathological hyperoxia induced lung injuries in the development of BPD. These results suggest that treating hyperoxia-induced lung injury with Hsp70 may reduce the risk of developing BPD.

A Full-term Infant with Seizures.

Hypoxic-ischemic (HI) encephalopathy remains a major cause of perinatal mortality and chronic disability in newborns worldwide (1–6 for 1000 births). The only current clinical treatment is hypothermia, which is efficient for less than 60% of babies. Mainly considered as a waste product in the past, lactate, in addition to glucose, is increasingly admitted as a supplementary fuel for neurons and, more recently, as a signaling molecule in the brain. Our aim was to investigate the neuroprotective effect of lactate in a neonatal (seven day old) rat model of hypoxia-ischemia. Pups received intra-peritoneal injection(s) of lactate (40 μmol). Size and apparent diffusion coefficients of brain lesions were assessed by magnetic resonance diffusion-weighted imaging. Oxiblot analyses and long-term behavioral studies were also conducted. A single lactate injection induced a 30% reduction in brain lesion volume, indicating a rapid and efficient neuroprotective effect. When oxamate, a lactate dehydrogenase inhibitor, was co-injected with lactate, the neuroprotection was completely abolished, highlighting the role of lactate metabolism in this protection. After three lactate injections (one per day), pups presented the smallest brain lesion volume and a complete recovery of neurological reflexes, sensorimotor capacities and long-term memory, demonstrating that lactate administration is a promising therapy for neonatal HI insult.

Dl-3-n-butylphthalide attenuates hypoxic-ischemic brain injury through inhibiting endoplasmic reticulum stress-induced cell apoptosis and alleviating blood-brain barrier disruption in newborn rats

Inasmuch as long-chain polyunsaturated fatty acids (PUFA, metabolites of the essential n-3 and n-6 fatty acids) are known to modulate inflammation, we hypothesized that supplementation of formula with these compounds would prevent necrotizing enterocolitis (NEC) and intestinal inflammation in our neonatal rat model. Newborn rats were stressed with asphyxia and formula feeding, and randomly assigned to control formula, control with PUFA supplementation, and PUFA with nucleotides. Animals were followed for 72--96 h and assessed for death, gross and histologic NEC, intestinal apoptosis, endotoxemia, and intestinal mRNA synthesis of phospholipase A(2)-II (rate-limiting enzyme for platelet activating factor production), platelet activating factor receptor, and inducible nitric oxide synthase. We found that PUFA reduced the incidence of death and NEC compared with the other groups (NEC 8 of 24 versus 17 of 24 control and 13 of 23 PUFA + nucleotides, p < 0.05). Furthermore, PUFA reduced plasma endotoxemia at 48 h (25 +/- 4 EU/mL versus 276 +/- 39 EU/mL in control and 170 +/- 28 EU/mL in PUFA + nucleotide), intestinal phospholipase A(2)-II expression at 24 h, and platelet activating factor receptor expression at 48 h. Formula supplementation had no effect on apoptosis of intestinal epithelium or intestinal inducible nitric oxide synthase expression. Addition of nucleotides with PUFA abrogated the beneficial effects of PUFA on intestinal inflammation. We conclude that PUFA reduces the incidence of NEC and intestinal inflammation in a neonatal rat model.

Effects of perinatal ivermectin exposure on behavioral development of rats

Dexmedetomidine (DEX) has been reported to alleviate hypoxic-ischemic brain damage (HIBD) in neonates. This study aimed to investigate whether DEX improves cognitive impairment by promoting hippocampal neurogenesis via the BDNF/TrkB/CREB signaling pathway in neonatal rats with HIBD. HIBD was induced in postnatal day 7 rats using the Rice-Vannucci method, and DEX (25 μg/kg) was administered intraperitoneally immediately after the HIBD induction. The BDNF/TrkB/CREB pathway was regulated by administering the TrkB receptor antagonist ANA-12 through intraperitoneal injection or by delivering adeno-associated virus (AAV)-shRNA-BDNF via intrahippocampal injection. Western blot was performed to measure the levels of BDNF, TrkB, and CREB. Immunofluorescence staining was utilized to identify the polarization of astrocytes and evaluate the levels of neurogenesis in the dentate gyrus of the hippocampus. Nissl and TTC staining were performed to evaluate the extent of neuronal damage. The MWM test was conducted to evaluate spatial learning and memory ability. The levels of BDNF and neurogenesis exhibited a notable decrease in the hippocampus of neonatal rats after HIBD, as determined by RNA-sequencing technology. Our results demonstrated that treatment with DEX effectively increased the protein expression of BDNF and the phosphorylation of TrkB and CREB, promoting neurogenesis in the dentate gyrus of the hippocampus in neonatal rats with HIBD. Specifically, DEX treatment significantly augmented the expression of BDNF in hippocampal astrocytes, while decreasing the proportion of detrimental A1 astrocytes and increasing the proportion of beneficial A2 astrocytes in neonatal rats with HIBD. Furthermore, inhibiting the BDNF/TrkB/CREB pathway using either ANA-12 or AAV-shRNA-BDNF significantly counteracted the advantageous outcomes of DEX on hippocampal neurogenesis, neuronal survival, and cognitive improvement. DEX promoted neurogenesis in the hippocampus by activating the BDNF/TrkB/CREB pathway through the induction of polarization of A1 astrocytes toward A2 astrocytes, subsequently mitigating neuronal damage and cognitive impairment in neonates with HIBD.

Neuroprotective effects of inter-alpha inhibitor proteins after hypoxic-ischemic brain injury in neonatal rats

Objective To evaluate the effects of ganglioside GM1 on hypoxic ischemic brain damage (HIBD) in neonatal rats and on the expression of potassium-chloride cotransporter 2 (KCC2) in hippocampus. Methods Seven-day-old Sprague-Dawley (SD) rats (n=72) were randomly divided into a sham group, an HIBD group and a ganglioside GM1 group. Each group was further divided into a 3 d subgroup and a 21 d subgroup according to the different detection index (n=12). Rat HIBD models were prepared according the Rice-Vannucci method. After HIBD, the ganglioside GM1 group was given ganglioside GM1 20 mg/(kg·d) by intraperitoneal injection for 3 d continuously. 2-, 3-, 5-triphenyltetrazolium chloride (TTC) was preformed to evaluate the area of cerebral infarction of HIBD in each 3 d subgroup. Spontaneous activity recorder was used to observe the locomotor activity of the rats in the 21 d subgroups. Morris water maze test was conducted for assessment of rats' learning and memory abilities in the 21 d subgroups. Western blot analysis was employed to determine the alterations in KCC2 expression in hippocampus in all the 3 d and 21 d subgroups. Results Compared with the HIBD group (28.6%±5.2%), the ratio of cerebral infarction volume in the ganglioside GM1 group (11.3%±2.4%) was significantly reduced (P<0.05). Compared with the HIBD group (289.6±61.3), the number of locomotor activities within 2 h in the ganglioside GM1 group (412.1±66.8) was significantly increased (P<0.05). Compared with the HIBD group, the escape latency was significantly reduced, but the percentage time of target quadrant and the number of crossing the platform were significantly increased in the ganglioside GM1 group (P<0.05). Three days and 21 days after HIBD, the expression of KCC2 in the ganglioside GM1 group was significantly higher than that in the HIBD group (P<0.05). Conclusion Ganglioside GM1 may have a significant protective effect on HIBD in neonatal rats, and its mechanism may be related to regulation of the expression of KCC2 in hippocampus. Key words: Ganglioside GM1; Hypoxic ischemic brain damage; Potassium-chloride cotransporter 2

Background: IAIPs are serine protease inhibitors that exert anti-inflammatory effects after HI brain injury. We have previously shown that IAIP administration after HI attenuates histopathological brain injury, apoptosis, and microglial activation and improves neurobehavioral outcomes in neonatal rats. Astrocytes are known to form glial scars, increase neuroinflammation, and exacerbate brain injury after stroke. Objective: To determine the effect of IAIPs on astrocytic GFAP expression in the neonatal rat brain after HI. Methods: HI was induced using the Rice-Vannucci method with right carotid ligation and exposure to 8% O 2 for 90 min. Post-natal day 7 rats were assigned to one of three groups: non-ischemic sham-control (Sham, n=12), HI exposed placebo-treated (HI-PL, n=13), or HI exposed IAIP-treated (HI-IAIP, n=14). Intraperitoneal injections of 30 mg/kg of IAIP or saline were given at 15 min, 24, and 48 h after HI. We recorded the sex of the rats. 72 h after HI, brains were collected, paraffin embedded, and sectioned. We performed immunohistochemical analysis by staining slides with GFAP, a marker of astrocyte activation. We performed stereological analysis by capturing images of the whole damaged hemisphere, cerebral cortex, hippocampus, and corpus callosum with the StereoInvestgator 10.0 Probe. We quantified GFAP expression levels using Image J software without knowledge of the group assignments. Results: Sham rats had significantly lower GFAP expression compared with the HI-PL group in the hemisphere (P&lt;0.001), cortex (P&lt;0.005), and hippocampus (P&lt;0.005). IAIP treatment significantly reduced GFAP expression after HI in the hemisphere (P&lt;0.05) compared with the HI-PL group. We also examined GFAP expression separately in male and female rats and found no differences in GFAP expression among the groups in females. However, we found that the Sham males had significantly lower GFAP expression compared to HI-PL in the hemisphere (P&lt;0.005), cortex (P&lt;0.005), and hippocampus (P&lt;0.005), and that the IAIP treated HI exposed males had lower GFAP expression compared with the HI-PL group in the hemisphere (P&lt;0.05) and cortex (P&lt;0.05). Conclusion: IAIPs attenuate HI related astrogliosis in some brain regions particularly in male neonatal rats.

Sal-hDPSCs Transplantation Alleviates Hypoxic-Ischaemic Ferroptosis in Neonatal Rats Via the FSP1-CoQ10 Axis.

Point:Counterpoint: The parafacial respiratory group (pFRG)/pre-Bötzinger complex (preBötC) is the primary site of respiratory rhythm generation in the mammal

Objectives Babassu coconut (Orbignya phalerata) is an important economic and nutritional resource for many rural communities in Brazil. Babassu oil (BO) contains low levels of essential fatty acids (EFAs), which are crucial nutrients for physical and neurological development. However, it remains unclear whether BO consumption can affect these aspects. We investigated somatic maturation, reflex ontogeny, anxiety-like behavior, and brain susceptibility to cortical spreading depression (CSD) in the offspring of rat dams fed a BO-diet. Methods Wistar dams were fed diets containing either BO or soybean oil (control) during gestation and lactation. After weaning, pups either continued their mothers’ diets or switched to the control diet. Offspring were analyzed during adolescence (groups Soy and Bab, n = 64) or adulthood (groups Soy-Soy, Bab-Bab and Bab-Soy, n = 26). Results Compared to controls, the Bab group showed developmental delays in reflex ontogeny (palmar grasp, cliff avoidance, and negative geotaxis, p < 0.05) and somatic maturation (ear unfolding, superior teeth eruption, eye opening, and ear opening, p < 0.05). At both ages, anxiety-like behavior (elevated-plus maze) did not differ between groups. For CSD, the Bab (adolescent) and Bab-Bab (adult) groups exhibited higher and lower CSD velocities, respectively, compared to age-matched controls (p < 0.001). This effect was not reversed in the Bab-Soy group. Discussion We suggest that BO consumption during pregnancy and lactation should be considered with caution, as it may pose premature and long-term risks to neurodevelopment and cortical excitability.

To determine the effect of Tanshinone IIA (TanIIA) on the phosphory-lated NMDA receptor 1 at Serine 897 site (phospho-NR1 S897) and intracellular free calcium concentration ([Ca(2+)](i)) in neonatal SD rats with hypoxic ischemic brain damage (HIBD), and to explore the neuroprotective mechanism of TanIIA in HIBD. Neonatal SD rats were randomly divided into a normal control, and an HIBD and TanIIA+HIBD group. Rice-Vannucci method was used for HIBD animal model. Time points were: 3, 6, 12, and 24 h after HIBD (n=10 in each group at each time point). TanIIA was intraperitoneally given at 1 μg/g every 12 h. Fura-2AM was used to mark the fluorescent calcium probe and [Ca(2+)](i) was measured by a Hitachi F-4500 Fluorescence Spectrophometer. Fluorescent immunohisotichemical study was used for the expression of phospho-NR1 S897. (1) Compared with the normal control group, both the [Ca(2+)](i) absolute number and ipsi-/contra-lateral ratio were increased at each time point with statistical significance (P<0.05). Compared with the HIBD group, the [Ca(2+)](i) in the HIBD+ TanIIA group was decreased at each time point. At 24 h after HIBD, the ipsi-/contra-lateral ratio of HIBD+ TanIIA group was 24.9% less than that of HIBD group with statistical significance (P<0.05). (2) In the normal control group, abundant phospho-NR1 S897 positive cells were nicely distributed in the cortex. Compared with the normal control group, at each time point, both the absolute number of phospho-NR1 S897 positive cells and the fluorescent intensity of phospho-NR1 S897 in the ipsilateral cortex of the HIBD group were decreased with statistical significance (P<0.05). Compared with the HIBD group, both the absolute number of phospho-NR1 S897 positive cells and the fluorescent intensity of phospho-NR1 S897 in the ipsilateral cortex of HIBD+ TanIIA were increased. There was significant difference at 3 and 12 h after the HIBD (P<0.05). TanIIA reduced the HIBD-caused down-regulation of phospho-NR1 S897 and the HIBD-caused [Ca(2+)](i) elevation in the cortex. The neuroprotective effect of TanIIA may be related to influencing NMDA receptor expression and decreasing intracellular free calcium aggregation.

Objective The study aimed to elucidate the role and the underlying mechanism of human epididymis protein 4 (HE4) in the pathogenesis of hyperoxia-induced bronchial dysplasia in newborn rats. Methods Forty neonatal Sprague–Dawley (SD) rats were separated into two groups: a normal control group (20.8% oxygen concentration) and a hyperoxia-induced group (85% oxygen concentration). Three time intervals of 24 h, 3 days and 7 days were chosen for each group. Haematoxylin–eosin staining was used to identify the pathological alterations in the lung tissue of the SD rats. Enzyme-linked immunosorbent assay was used to evaluate plasma protein levels. Real-time reverse transcription polymerase chain reaction was used to determine messenger RNA (mRNA) expression. Results In newborn SD rats, hyperoxia intervention within 7 days may result in acute lung damage. In the plasma and tissue of newborn SD rats, hyperoxia induction may raise levels of HE4, matrix metalloproteinases (MMP) 9 and tissue inhibitors of metalloproteinases (TIMP) 1. We discovered that the HE4 protein activates the phosphorylation of extracellular regulated protein kinases (ERK) and p65, activates the downstream MMP9 signalling pathway, inhibits MMP9 mRNA expression, inhibits protein activity, reduces type I collagen degradation, increases collagen secretion and promotes matrix remodelling and fibrosis in neonatal rat primary alveolar type II epithelial cells by overexpressing and silencing the HE4 gene. Conclusion Through the ERK, MMP9 and TIMP1 signalling pathways, HE4 mediates the pathophysiological process of hyperoxia-induced lung damage in rats. Lung damage and lung basal remodelling are mediated by HE4 overexpression.