Developmental expression of endothelin receptors in postnatal swine mesenteric artery

Studies were conducted to determine whether endothelin (ET) ETA and ETB receptor protein and mRNA expression is developmentally regulated in the postnatal swine mesenteric circulation. To this end, Western blotting and real-time reverse PCR were performed on protein and total RNA isolated from the mesenteric artery harvested from 3-, 10-, and 30-d-old swine. Western blot analysis revealed that ETA and ETB receptor protein expression in the swine mesenteric artery decreased over the age range studied; thus, ETA and ETB receptor protein expression was significantly greater in the 3-d-old group then progressively declined over the first postnatal month. Similar to the Western data, real-time PCR analysis revealed that ETA and ETB receptor mRNA expression also decreased over the age range studied; thus, ETA and ETB receptor mRNA expression was significantly greater in the 3-d-old group then progressively declined over the first postnatal month. Immunohistochemistry localized the ETA receptor to the vascular smooth muscle and the ETB receptor to the endothelial cell layer. Additionally, we report a partial cDNA sequence for the swine ETB receptor. We conclude that ETA and ETB receptor protein and mRNA expression is developmentally regulated in the postnatal swine mesenteric artery, being expressed to a greater degree in younger animals.     

Endothelin B receptor blockade attenuates pulmonary vasodilation in oxygen-ventilated fetal lambs

BACKGROUND: Endothelin-1 (ET-1) contributes to the regulation of pulmonary vascular tone in the normal ovine fetus and in models of perinatal pulmonary hypertension. In the fetal lamb lung, the effects of ET-1 depend on the balance of at least two endothelin receptor subtypes: ETA and ETB. ETA receptors are located on smooth muscle cells and mediate vasoconstriction and smooth muscle proliferation. Stimulation of endothelial ETB receptors causes vasodilation through release of nitric oxide and also functions to remove ET-1 from the circulation. However, whether activation of ETB receptors contributes to the fall in pulmonary vascular tone at birth is unknown. OBJECTIVE AND METHODS: To determine the role of acute ETB receptor blockade in pulmonary vasodilation in response to birth-related stimuli, we studied the hemodynamic effects of selective ETB receptor blockade with BQ-788 during mechanical ventilation with low (<10%) and high FiO2 (100%) in near-term fetal sheep. RESULTS: Intrapulmonary infusion of BQ-788 did not change left pulmonary artery (LPA) blood flow and pulmonary vascular resistance (PVR) at baseline. In comparison with controls, BQ-788 treatment attenuated the rise in LPA flow with low and high FiO2 ventilation (p <0.001 vs. control for each FiO2 concentration). PVR progressively decreased during mechanical ventilation with low and high FiO2 in both groups, but PVR remained higher after BQ-788 treatment throughout the study period (p <0.001). CONCLUSIONS: We conclude that selective ETB receptor blockade attenuates pulmonary vasodilation at birth. We speculate that ETB receptor stimulation contributes to pulmonary vasodilation at birth in the ovine fetus.     

Altered regulation of the ET-1 cascade in lambs with increased pulmonary blood flow and pulmonary hypertension

Plasma concentrations of endothelin-1 (ET-1) are increased in children with congenital heart disease associated with increased pulmonary blood flow. However, the role of ET-1 in the pathophysiology of pulmonary hypertension remains unclear. Preproendothelin-1 gene expression is increased in adults with advanced pulmonary hypertension. To characterize potential early molecular alterations in the ET-1 cascade induced by increased pulmonary blood flow and pulmonary hypertension, fetal lambs underwent in utero placement of an aortopulmonary vascular graft (shunt). RNase protection assays and Western blot analysis were performed on lung tissue prepared from 4-wk-old shunt lambs and age-matched controls. Endothelin-converting enzyme-1 [the enzyme responsible for the production of active ET-1 from big ET-1, mRNA (411%, p<0.05)] and protein (170%, p<0.05) were increased in lung tissue prepared from shunt lambs, compared with age-matched controls. Endothelin type A receptor (the receptor that mediates vasoconstriction), mRNA (246%, p<0.05), and protein (176%, p<0.05) also were increased in lung tissue prepared from shunt lambs compared with age-matched controls. Conversely, endothelin type B receptor (the receptor that mediates vasodilation), mRNA (46%, p<0.05), and protein (65%, p<0.05) were decreased in shunt lambs. Both the mRNA and protein levels for preproendothelin-were unchanged. Thus we conclude that increased pulmonary blood flow and pulmonary hypertension induce early alterations in the ET-1 cascade that result in increased ET-1 production, increased ET-1-mediated vasoconstriction, and decreased vasodilation. These early alterations in gene expression may contribute to the development of pulmonary hypertension and its associated enhanced pulmonary vascular reactivity.     

Antenatal betamethasone administration has a dual effect on adult sheep vascular reactivity

The effect of antenatal steroids on blood pressure in humans remains an unresolved question. Here we report the effects of prenatal exposure to clinically relevant doses of betamethasone on endothelial and/or vascular smooth muscle function. Pregnant sheep were randomly treated with betamethasone (0.17 mg/kg) or vehicle at 80 and 81 d of gestation. We studied arterial segments (4th-5th generation) of the right brachial artery obtained at 1-2 y of age under general anesthesia. We demonstrate that in brachial arteries of steroid exposed offspring: KCl induced contraction is increased after endothelium removal or incubation with inhibitors of nitric oxide synthase or cyclooxygenase; acetylcholine-induced relaxation is increased; sensitivity to endothelin-1 (ET-1) is increased and this effect is decreased by the ETB antagonist BQ-788. These data suggest that, in sheep treated with clinically relevant doses of betamethasone at a gestational stage when human fetuses are routinely exposed to glucocorticoids, there is a dual effect of betamethasone on the adult sheep brachial artery, i.e. endothelial dysfunction with an impairment of endothelin-1 ETB receptor-induced release of nitric oxide and an increased contribution of the ETB receptor in smooth muscle to the contractile effects of ET-1.     

Maternal nicotine effects on vascular endothelial growth factor expression and morphometry in rat lungs

Aims

Maternal smoking during pregnancy may impair pulmonary function in infants, and the exact mechanisms underlying these changes are unknown. We evaluated the effects of maternal nicotine exposure on lung VEGF expression and morphometry during the postnatal period in rats.

Methods and results

Timed pregnant Sprague–Dawley rats were injected subcutaneously with nicotine at a dose of 2 mg/kg/day from Day 3 to Day 21 of gestation. A control group was injected with saline. Body weight, lung weight, and lung volume were comparable between control and nicotine-exposed rats. Plasma vascular endothelial growth factor (VEGF) levels and lung VEGF mRNA expression decreased with advancing age, and nicotine exposure insignificantly decreased plasma VEGF levels and lung VEGF mRNA expression, compared with the control rats during the study period. Nicotine exposure caused a significant decrease in vascular endothelial growth factor receptor (VEGFR)-2 mRNA expression, compared with the level of the control rats on Postnatal Day 1. On Postnatal Day 1, nicotine-exposed rats exhibited a significantly lower volume fraction of alveolar airspace and alveolar surface area and a significantly higher alveolar wall volume fraction than did the control rats.

Conclusions

Maternal nicotine exposure during pregnancy decreases VEGF and VEGFR-2 mRNA expression and alters lung structure in the lungs of postnatal rats. Because angiogenesis is vital for alveolarization during normal lung development, these results suggest that decreased VEGF expression might be involved in the structural alterations of the developing lung after exposure to antenatal nicotine.     

Intestinal microcirculatory dysfunction during the development of experimental necrotizing enterocolitis

The aim of this study was to evaluate changes in intestinal microcirculation during necrotizing enterocolitis (NEC) and to examine the effect of endothelin (ET)-1 on the intestinal microcirculation. Prematurely born rats were either hand-fed formula (NEC) or dam fed (DF) and were exposed to asphyxia and cold stress twice daily to induce disease. At 0, 2, 3, and 4 d after the birth, the microcirculation in the ileum was examined using in vivo microscopic methods. The nutritive microvascular perfusion in the NEC group was progressively compromised from d 3 to d 4 (35% and 50% decrease, respectively) when compared with DF rats. Concomitantly, intestinal blood flow assessed by laser Doppler flowmetry was significantly reduced at d 2, 3, and 4 (by 31%, 36%, and 73%, respectively). Levels of ET-1 mRNA in the ileum were increased 3.7-fold. Microvascular responses to topically applied ET-1 were significantly increased in the NEC group, which was associated with decreased expression of ETB receptor. These results suggest that microcirculatory dysfunction in the distal ileum of neonatal rats with NEC contributes to disease progression and that enhanced microvascular responsiveness to ET-1 may participate in these microcirculatory disturbances.     

Attenuated endothelin- mRNA expression with endothelin- receptor blockade during hypoxaemia and reoxygenation in newborn piglets

We investigated the cause of decreased plasma endothelin-1 (ET-1) during hypoxaemia and reoxygenation in newborn piglets subjected to simultaneous blocking of the ET-1 receptors. Changes in plasma ET-1 and prepro-ET-1 mRNA expression in the main pulmonary artery and the left lower lobe in the lung were studied in 1-2-d-old piglets. Ten minutes prior to hypoxaemia, the hypoxaemia group (n = 10) was given saline, two groups (both n = 9) were given 1 and 5 mg/kg i.v. SB 217242 (an ET-1 receptor antagonist). Two groups served as normoxic controls, with and without SB 217242 5 mg/kg i.v. Hypoxaemia was induced by ventilating with 8% O2 until base excess was <-20 mmol/l or mean arterial blood pressure was <20 mmHg. Reoxygenation was performed for 2 h with room air. During hypoxaemia, plasma ET-1 decreased in the hypoxaemia group, remained unchanged in the 1-mg group and increased in the 5-mg group. At the end of reoxygenation, plasma ET-1 was above baseline in the 1-mg and 5-mg groups. In the pulmonary artery, the hypoxaemia group showed 2- to 5-fold higher prepro-ET- 1 mRNA expression compared to all the other groups (p < 0.05). There were trends for higher prepro-ET-1 mRNA expression in pulmonary tissue in the hypoxaemia group compared to the two receptor-blocking groups (p < 0.07). CONCLUSIONS: We conclude that hypoxaemia and reoxygenation increase prepro-ET-1 mRNA expression in the pulmonary artery in newborn piglets. These observations suggest that the half-life of ET-1 is decreased during hypoxaemia and reoxygenation in newborn piglets.     

Acute effect of a dual ETA�CETB receptor antagonist on pulmonary arterial vasculature in preterm lamb fetuses with surgically induced diaphragmatic hernia

Purpose  

To study the effects of tezosentan, a dual ETA and ETB receptor antagonist on the cardiopulmonary profile in a fetal lamb model of CDH in utero.     

Maternal caffeine intake has minor effects on adenosine receptor ontogeny in the rat brain

Maternal caffeine intake has been suggested to influence the offspring. We have studied the effects of maternal caffeine intake on adenosine and GABA receptors, targets for caffeine, during development of the rat brain. Caffeine (0.3 g/L) was added to the drinking water of rat dams during pregnancy and early postnatal life. Adenosine A1 and A2A and GABAA receptor development was studied using receptor autoradiography and in situ hybridization. Pups were examined on embryonic d 14 (E14), E18, E21, 2 h after birth (P2h), P24h, postnatal d 3 (P3), P7, P14, and P21. Adenosine A, receptor mRNA was detected at E14 and receptors at E18. A1 mRNA levels increased from the level reached at E18 between P3 and P14 (maximally a doubling), whereas A, receptors, studied by [3H]-1,3-dipropyl-8-cyclopentyl xanthine binding, increased later and to a much larger extent (about 10-fold) postnatally. Caffeine treatment had no significant effect on adenosine A1 receptors or on A1 receptor mRNA. A2A mRNA had reached adult levels by E18, whereas receptor levels were low or undetectable before birth and increased dramatically until P14. Caffeine did not influence A2A receptors or A2A receptor mRNA at any stage during development. [3H]-flunitrazepam binding, representing GABAA receptors, showed large regional variations during ontogeny, but there were no clear differences between the caffeine-exposed and the nonexposed pups. Thus, exposure to a low dose of caffeine during gestation and postnatal life had only minor effects on development of adenosine A, and A2A receptors and GABAA receptors in the rat brain.     

脑源性神经营养因子及其受体TrkB在肺炎链球菌脑膜炎炎症细胞中的表达

目的研究脑源性神经营养因子(BDNF)及其受体在细菌性脑膜炎炎症细胞中的表达,探讨炎症性脑损伤时BDNF的免疫调节作用。方法建立3周龄大鼠细菌性脑膜炎模型和正常对照模型,分别于细菌接种后24 h进行免疫组化染色、原位杂交等检测,观察BDNF蛋白、BDNF mRNA和TrkB mRNA在渗出炎症细胞中的表达。结果感染24 h后大鼠软脑膜、蛛网膜下隙及脑室内,均可见渗出的炎性细胞,同时表达BDNF蛋白、BDNF mRNA和TrkB mRNA。结论在细菌性脑膜炎炎症反应过程中,炎症渗出通过BDNF产生神经保护作用,并可能通过炎症细胞表达TrkB受体发挥调节免疫功能的效应。细菌性脑膜炎炎症反应过程中可能存在保护和破坏两个相互拮抗又相互作用的系统,共同影响着病情发展的势态。     

Prostaglandin E2 receptor expression in fetal baboon lung at 0.7 gestation after betamethasone exposure

The fetal lung produces and metabolizes prostaglandin (PG) E2. In vitro PGE2 induces surfactant production via E prostaglandin (EP)1 and cyclic adenosine monophosphate (cAMP)-coupled EP (EP2 and EP4) receptors. Glucocorticoids alter PG function and increase lung function in preterm neonates. We hypothesized that fetal exposure to maternally administered betamethasone (betaM) enhances fetal lung EP1 and cAMP-coupled EP receptor expression. Pregnant baboons were injected intramuscularly (i.m.) with either betaM (n=7) or saline [control (CTR); n=8] at 0.7 gestation. Fetal lungs were removed at cesarean section 48 h after the first injection. We determined mRNA levels, protein localization and abundance for all four PGE2 receptors by real-time polymerase chain reaction (PCR), immunohistochemistry, and Western blot. EP receptors were widely distributed in bronchiolar epithelium, bronchiolar smooth muscle, and endothelium and media of blood vessels, but not alveoli. Compared with CTR, betaM exposure resulted in a twofold EP2 mRNA decrease (p<0.05) in male fetuses only. EP1, EP3, and EP4 receptor mRNA levels were unaffected. Western blot analysis showed no alteration in EP receptor protein expression. In summary, this is the first demonstration of the four EP receptors in fetal lung. The only change after 48-h betaM exposure was a gender-specific decrease in EP2 receptor mRNA.     

胰岛素样生长因子-1(IGF-1)对缺氧缺血脑损伤新生鼠内源性IGF-1和IGF-1受体基因表达的影响

目的　胰岛素样生长因子 1(IGF 1)对损伤的神经组织有修复作用 ,但外源性IGF 1是否会抑制内源性IGF 1、IGF 1受体的生成 ,从而减弱IGF 1的神经保护作用尚不明确。本文通过观察IGF 1治疗新生大鼠缺血缺氧脑损伤 (HIBD)后脑IGF 1和IGF 1受体mRNA水平的变化 ,研究IGF 1对HIBD新生大鼠内源性IGF 1、IGF 1受体的影响。方法　制作新生大鼠HIBD模型 ,用原位杂交方法观察HIBD后各时间点海马和大脑皮层IGF 1和IGF 1受体基因表达的动态变化 ,并比较IGF 1治疗组与未治疗组HIBD后 12h、72hIGF 1、IGF 1受体mRNA的表达水平。结果　HIBD后 4 8h海马IGF 1和IGF 1受体mRNA开始升高 ,72h达高峰。损伤后 12 0h ,IGF 1mRNA降至正常水平 ,而IGF 1受体mRNA仍处于较高水平。在皮层 ,IGF 1和IGF 1受体mRNA开始升高时间稍早于海马 ,2 4h上升 ,96h降至正常 ,但是上升幅度相对较小。与未治疗组比较 ,IGF 1治疗后内源性IGF 1表达无明显变化。IGF 1受体的表达在治疗后 12h无明显差别 ,但在 72h时显著增加。结论　HIBD后皮层、海马等脑损伤区的IGF 1和IGF 1受体表达均升高。给予外源性IGF 1后并不降低内源性IGF 1的表达 ,还能刺激IGF 1受体表达增加。     

缺氧缺血性脑损伤新生大鼠脑组织MMP-9和TIMP-1表达的动态变化研究

目的 探讨新生大鼠缺氧缺血性脑损伤(HIBD)的发生机制.方法 建立新生大鼠HIBD模型,随机分为假手术组及HIBD 6 h、12 h、24 h、48 h、72 h组,每组6只.观察脑组织大体病理学改变.采用Real-time Q-PCR方法测定大鼠脑组织MMP-9 mRNA和TIMP-1 mRNA表达.结果 (1)新生大鼠HIBD后12～48 h脑水肿明显,可见点状软化坏死灶.(2)假手术组大鼠MMP-9 mRNA表达水平极低,HIBD组大鼠在缺氧缺血6 h表达开始增高,24 h达高峰,此后渐渐下降,但72 h仍维持较高的水平,与假手术组相比差异有非常显著性(P＜0.01).(3)假手术组大鼠TIMP-1 mRNA表达水平极低,HIBD组大鼠在经历缺氧缺血6、12、24h,TIMP-1 mRNA表达水平有微弱升高,与假手术组相比差异有显著性(P＜0.05),但48 h后TIMP-1 mRNA表达下降到假手术组水平(P＞0.05).(4)MMP-9 mRNA/TIMP-1 mRNA比值在假手术组接近1:1,HIBD组缺氧缺血12 h后比值升高,在48 h达到高峰,72 h有所下降,但仍高于假手术组(P＜0.01).结论 新生大鼠HIBD后可诱导MMP-9 mRNA表达,而MMP-9 mRNA和TIMP-1 mRNA表达的失衡可能参与了HIBD的发病过程.     

胰岛素样生长因子-1(IGF-1)对缺氧缺血脑损伤新生鼠内源性IGF-1和IGF-1受体基因表达的影响

目的　胰岛素样生长因子 1(IGF 1)对损伤的神经组织有修复作用 ,但外源性IGF 1是否会抑制内源性IGF 1、IGF 1受体的生成 ,从而减弱IGF 1的神经保护作用尚不明确。本文通过观察IGF 1治疗新生大鼠缺血缺氧脑损伤 (HIBD)后脑IGF 1和IGF 1受体mRNA水平的变化 ,研究IGF 1对HIBD新生大鼠内源性IGF 1、IGF 1受体的影响。方法　制作新生大鼠HIBD模型 ,用原位杂交方法观察HIBD后各时间点海马和大脑皮层IGF 1和IGF 1受体基因表达的动态变化 ,并比较IGF 1治疗组与未治疗组HIBD后 12h、72hIGF 1、IGF 1受体mRNA的表达水平。结果　HIBD后 4 8h海马IGF 1和IGF 1受体mRNA开始升高 ,72h达高峰。损伤后 12 0h ,IGF 1mRNA降至正常水平 ,而IGF 1受体mRNA仍处于较高水平。在皮层 ,IGF 1和IGF 1受体mRNA开始升高时间稍早于海马 ,2 4h上升 ,96h降至正常 ,但是上升幅度相对较小。与未治疗组比较 ,IGF 1治疗后内源性IGF 1表达无明显变化。IGF 1受体的表达在治疗后 12h无明显差别 ,但在 72h时显著增加。结论　HIBD后皮层、海马等脑损伤区的IGF 1和IGF 1受体表达均升高。给予外源性IGF 1后并不降低内源性IGF 1的表达 ,还能刺激IGF 1受体表达增加。     

Antenatal treatment with corticosteroids affects mRNA expression of dopamine D1 and D2 receptors in the striatum of developing rabbit

The expression levels of dopamine D1 and D2 receptor mRNA have been investigated using Northern blot analysis in developing rabbit striatum after antenatal exposure to betamethasone. Pregnant rabbits were given either 0.1 mg/kg betamethasone or 0.1 mg/kg saline doses twice within 24 h. Dopamine D1 receptor mRNA levels were found significantly higher in the fetuses exposed to antenatal betamethasone than in the saline-treated controls. After birth, dopamine D1 and D2 receptor mRNA levels were both significantly lower in 1- and 25-day-old treated pups but recovered to normal levels in adulthood. These data suggest that antenatal exposure to betamethasone can lead to lasting abnormalities.     

Betamethasone attenuates oxidant stress in endothelial cells from fetal lambs with persistent pulmonary hypertension

We investigated the effects of betamethasone on oxidative stress and impaired vasodilation in a lamb model of persistent pulmonary hypertension (PPHN). We treated pregnant ewes following fetal ductal ligation with betamethasone or saline for 48 h before delivery. Response of fetal pulmonary arteries to nitric oxide synthase (NOS) agonist adenosine triphosphate (ATP) and nitric oxide (NO) donor, s-nitroso-n-acetyl-penicillamine (SNAP) was determined in tissue bath. Pulmonary artery endothelial cells (PAEC) from fetal lambs with ductal ligation or sham ligation were treated with betamethasone or its vehicle for 48 h. Expression of endothelial NOS (eNOS), endothelin, endothelin-B (ET-B) receptor, and CuZn- and Mn-superoxide dismutase (SOD) in PAEC was studied. Intracellular cGMP and superoxide levels and interaction of eNOS with heat shock protein 90 (Hsp90) were determined in PAEC. Antenatal betamethasone improved the relaxation response of pulmonary arteries to ATP and SNAP in PPHN. PPHN was associated with decreases in eNOS and ET-B receptor and increase in prepro-endothelin mRNA levels. Betamethasone decreased prepro-endothelin mRNA and ET-1 pro-peptide levels and increased eNOS and MnSOD protein levels in PPHN. Betamethasone reversed the increased superoxide/decreased cGMP levels and restored Hsp90-eNOS interactions in PPHN. Betamethasone reduces oxidative stress and improves response of pulmonary arteries to vasodilators in lambs with PPHN.     

早产鼠高氧暴露后肺组织血管内皮生长因子和一氧化氮合酶的动态变化及相互关系

目的：最近研究表明,血管内皮生长因子（VEGF）及内皮型一氧化氮合酶(eNOS)功能的缺失,在支气管肺发育不良（BPD）发病机制中发挥了重要的作用。该文通过动态观察持续中浓度高氧暴露（60％O2）对早产大鼠肺内VGEF蛋白及mRNA和eNOS蛋白及mRNA表达的影响,探讨BPD的发病机制。方法：将21 d 孕早产鼠随机分为高氧暴露组(简称高氧组) 和空气对照组(简称空气组) ,分别置于常压高氧仓中（60％O2）和正常空气中暴露。分别于生后1,4,7,11,14 d每组各处死6只大鼠,留取肺组织标本。苏木精-伊红染色观察病理改变,免疫组化检测VEGF和eNOS蛋白表达,逆转录-聚合酶链反应方法检测VEGF和eNOS mRNA表达。结果：早产鼠高氧暴露4 d后出现肺泡间隔减少,微血管发育异常,间质纤维化,且病变随着高氧暴露时间的延长而加重。高氧组大鼠第4,7天时肺组织VEGF蛋白表达明显低于相应空气对照组(P< 0. 05), VEGF mRNA表达亦显著减少(P< 0. 05)。随着暴露时间的延长,VEGF蛋白和mRNA进行性降低。高氧组大鼠在高氧暴露过程中肺组织eNOS蛋白和mRNA表达亦随着暴露时间的延长而降低。结论：高氧暴露导致早产鼠肺组织VEGF和eNOS表达持续性减少,微血管发育异常和肺泡化受阻。这些由高氧暴露诱导产生的BPD样损害,可能与VEGF和eNOS的表达下调有关,且二者之间存在着密切的联系。［中国当代儿科杂志,2007,9（5）：473-478］     

碱性成纤维细胞生长因子对新生大鼠缺氧缺血性脑损伤防治作用及其机制的探讨

目的　探讨碱性成纤维细胞生长因子（bFGF）对新生大鼠缺氧缺血性脑损伤（HIBD）的防治作用及其机制。方法　将63只7日龄wistar大鼠分为假手术对照组15只、HIBD组18只和bFGF治疗组30只（17.5μg/kg12只,10μg/kg18只）。制备大鼠HIBD模型,给予治疗组大鼠连续7d腹腔注射bFGF,对HIBD组腹腔注射等体积生理盐水作为对照,全部大鼠于术后14d处死,观察脑的大体、光镜及电镜下的改变;另取鼠72只（bFGF组12只,未治疗组48只,对照组12只）制备HIBD模型,利用逆转录-聚合酶链式反应（RT-PCR）技术检测新生大鼠HIBD后不同时间脑皮质细胞间粘附分子1（ICAM-1）mRNA的表达及bFGF干预对它的影响。结果　新生大鼠HIBD后2周脑大体改变明显,脑萎缩、脑软化及空洞形成的发生率分别为73.3%、60.0%和26.7%。bFGF治疗可降低脑萎缩、脑软化的发生率（31.0%、24.1%）（P＜0.05）。电镜下可见bFGF对HIBD后的神经元、血管内皮细胞及神经胶质细胞的超微结构均有明显的促修复作用。HIBD6h后,ICAM-1mRNA开始明显增高,24h达高峰,7d基本恢复至正常水平。高峰表达时病侧脑ICAM-1mRNA为正常组的3.6倍(P＜0.01),为健侧脑的2.2倍(P＜0.05)。bFGF干预组ICAM-1mRNA表达低于HIBD组(P＜0.05)。结论　bFGF对新生大鼠HIBD具有防治作用,其机制可能是通过影响受损神经元的物质代谢、抑制HIBD后ICAM-1mRNA的过度表达而加快神经再生修复。     

促炎症细胞因子对新生猪肺泡Ⅱ型上皮细胞相关生长因子表达的影响

目的 建立出生后1～3 d新生猪肺泡Ⅱ型上皮细胞(AEC-Ⅱ)体外分离纯化及鉴定方法,探讨促炎症细胞因子对AEC-Ⅱ长因子(GFs)的影响,比较不同消化酶溶液、纯化方法获得细胞产量、活力及AEC-Ⅱ纯度的差异.方法 原代培养AEC-Ⅱ24 h给予不同浓度IL-1β、IL-6刺激48 h,观察AEC-Ⅱ增殖变化,RT-PCR检测胰岛素样生长因子-1(IGF-Ⅰ)、血小板源性生长因子(PDGF)、表面活性物质蛋白(SP)-A及-B mRNA的表达情况,并检测IGF-Ⅰ抗体对AEC-Ⅱ增殖及SP-A、SP-B mRNA表达的影响.结果 30000 U/L弹力蛋白酶/0.1%胰酶在37℃下消化新生猪肺组织20 min获得细胞产量为(5.33±0.54)×106/g(肺重+心重),显著高于其他各组(P<0.01).免疫黏附法纯化AEC-Ⅱ产量明显高于Percoll法,为(38.0±28.0)×106/头新生猪.AEC-Ⅱ原代培养24～96 h状态最佳.随IL-1β、IL-6刺激浓度升高,AEC-Ⅱ增殖能力及IGF-Ⅰ及SP-A mRNA表达水平降低,但PDGF、SP-B mRNA的表达无明显变化.IGF-Ⅰ抗体刺激下,AEC-Ⅱ增殖能力及SP-A、SP-B mRNA表达水平均降低.结论 IL-1B、IL-6可能通过调节AEC-Ⅱ中IGF-Ⅰ mRNA的表达影响细胞的增殖及功能.