Effects of hypoxia on differentiation from human placenta-derived mesenchymal stem cells to nucleus pulposus-like cells

Background context

Low back pain is a frequently occurring disease caused by intervertebral disc degeneration. Mesenchymal stem cells (MSCs) are a possible treatment modality. Studies have shown MSCs can be transformed into nucleus pulposus-like cells under normoxic conditions. However, this is not a true representation of the hypoxic environment nucleus pulposus cells experience during in vivo growth and differentiation.

Purpose

To determine the effects of a hypoxic environment on the differentiation of human placenta-derived mesenchymal stem cells (PMSCs) to nucleus pulposus-like cells.

Study design

An experimental study.

Methods

Placenta-derived mesenchymal stem cells were cultured and the mesenchymal lineage was confirmed by flow cytometry. Two groups of PMSCs were then cultured under different oxygen concentrations creating a hypoxic group and normoxic group. The proliferation of cells in each group was compared by cell counting kit-8 on Day 1, 3, 5, and 7. Real-time polymerase chain reaction on Days 3 and 7 compared the expressions of Sox-9, Type II collagen, aggrecan, and hypoxia inducible factor-1α (HIF-1α) between the two groups. Immunofluorescence was used to compare the expression of Type II collagen between the two groups after 14 days.

Results

Placenta-derived mesenchymal stem cells were successfully isolated and cultured. Mesenchymal markers were positive. On Days 3 and 5, the hypoxic group had a significantly higher proliferation rate than the normoxic group (p<.05). The expression of Sox-9 and HIF-1α was significantly higher (p<.05) in the hypoxic group at Days 3 and 7. Type II collagen and aggrecan expressions were significantly higher (p<.05) in the hypoxic group at Day 7. The hypoxic group stained more positive for Type II collagen at Day 14.

Conclusions

Hypoxic conditions lead to an increased differentiation and proliferation of nucleus pulposus-like cells. Placenta-derived mesenchymal stem cells cultured in nucleus pulposus inducing media and a hypoxic environment show enhanced expression of the nucleus pulposus-like cell markers, Sox-9, Type II collagen, aggrecan, and HIF-1α.     

三氧治疗联合调强适形放疗治疗鼻咽癌及对患者血清乏氧诱导因子-1α及血管内皮生长因子的影响

目的：研究分析三氧治疗联合调强适形放疗治疗鼻咽癌的疗效及对患者血清乏氧诱导因子-1α（HIF-1α）及血管内皮生长因子（VEGF）的影响。方法选取我院2010年1月～2013年12月收治的鼻咽癌放疗患者50例进行治疗观察,随机分为两组,每组各25例。对照组行调强放疗,观察组在对照组治疗基础上行三氧联合治疗。结果治疗后,观察组鼻咽癌患者血清HIF-1α水平显著下降,对照组则显著升高,差异均有统计学意义（P＜0.01～0.05）。治疗后,观察组鼻咽癌患者血清HIF-1α水平显著低于对照组,差异有统计学意义（P＜0.01）。治疗后,观察组鼻咽癌患者血清VEGF水平显著下降,对照组则显著升高,差异均有统计学意义（P＜0.01）。治疗后,观察组鼻咽癌患者血清VEGF水平显著低于对照组,差异有统计学意义（P＜0.01）。结论三氧治疗联合调强适形放疗治疗鼻咽癌的疗效显著,能改善患者的血清乏氧诱导因子-1α及血管内皮生长因子水平。     

缺氧诱导因子HIF-1α、3α在血管瘤不同时期的表达和意义

目的 探讨缺氧在血管瘤不同时期的表达和作用.方法 采用免疫组化SP法测定24例增生期血管瘤和18例消退期血管瘤中缺氧染色阳性率,HIF-1α、HIF-3α、VEGF、Ki-67和细胞凋亡表达情况.结果 24例增生期血管瘤中缺氧染色阳性率为80%(19/24),HIF-1α阳性指数为(23.40±4.73)、HIF-3α为(7.90±2.15)、VEGF为(16.90±3.34)、Ki-67为(57.60±11.33)、细胞凋亡指数为(4.50±1.51);而消退期血管瘤中缺氧染色阳性率为90%(16/18),HIF-1α为(9.50±2.67)、HIF-3α为(19.80±2.43)、VEGF为(2.70±0.32)、Ki-67为(11.20±2.65)、细胞凋亡指数为(11.40±2.67).不同时期血管瘤表达的HIF-1α、HIF-3α、VEGF、Ki-67、细胞凋亡指数均有显著性差别(P＜0.05).结论 缺氧是血管瘤不同时期的普遍现象,但对增殖期血管瘤的作用是通过HIF-1α促进内皮细胞繁殖,而对消退期血管瘤是通过HIF-3α促进其凋亡.     

Influence of hypoxia on mitochondrial function and energy status in CCl4-induced cirrhotic rat liver

The influence of hypoxia on hepatic mitochondrial function and energy status was studied in normal and carbon tetrachloride (CCl4)-induced cirrhotic rats. Under hypoxemia of 50 mm Hg-PaO2, hepatic energy status was suppressed both in normal and cirrhotic rats. After the reversal of hypoxia, it was completely restored in normal rats concomitant with a rapid elevation of hepatic mitochondrial redox state (overshoot phenomenon) and increase in the mitochondrial oxidative phosphorylative activity. By contrast, in cirrhotic rats, such an enhancement of mitochondrial function was not observed. It was clarified that cirrhotic liver mitochondrial function was not observed. It was clarified that cirrhotic liver mitochondria have little capacity to respond to the hypoxic stress. A lower resistance to hypoxic episode in cirrhotics might be attributable to the absence of mitochondrial enhancement which is a compensatory mechanism for the deranged energy metabolism of the liver.     

参知健脑方对缺氧致认知功能障碍大鼠脑线粒体损伤的保护机制研究

目的:从线粒体角度观察参知健脑方对缺氧致认知功能障碍大鼠线粒体损伤的保护机制的研究。方法:将老年大鼠随机分为3组,建立缺氧致线粒体损伤的认知功能障碍模型组以及参知健脑方(SZJ)干预组,并用Morris水迷宫对大鼠的学习记忆能力进行检测。采用酶联免疫吸附法(ELISA)检测线粒体细胞色素氧化酶(COX)的活性、8羟基脱氧鸟苷(8-OHdG)、β-淀粉样前体蛋白(βAPP)及β-淀粉样蛋白(Aβ_(1-42))的含量,观察4个指标与认知功能障碍之间的关联性,进而观察缺氧对模型组脑线粒体的影响及SZJ干预组对脑线粒体的保护作用。结果:持续低压缺氧造模脑组织中APP、Aβ_(1-42)含量模型组与正常组、SZJ干预组间均有统计学意义(P0.01),8-OHdG含量模型组与正常组、SZJ干预组间比较有统计学意义(P0.01),SZJ干预组与正常组间比较有统计学意义(P0.05),COX含量正常组与模型组间比较有统计学意义(P0.01)、模型组与SZJ干预组比较有统计学意义(P0.05)。结论:参知健脑方可以抑制APP、Aβ_(1-42)的积累、DNA氧化损伤、增强脑线粒体COX的活性,从而保护线粒体发挥神经保护作用,进一步改善缺氧对认知功能障碍学习记忆能力的影响为参知健脑方的临床应用提供实验支持。     

FGF2的生物信息学分析及其在低氧神经保护中的作用研究*

目的: 观察FGF2在低氧及低氧预适应条件下小鼠海马神经元细胞中的表达变化,探究FGF2是否参与低氧耐受神经保护作用。方法: 使用生物信息学方法进行搜索和鉴定FGF2基因家族成员。在细胞层面建立低氧和低氧预适应模型,通过Western-blot、qRT-PCR检测细胞中FGF2表达情况。结果: FGFs家族分为7个亚家族,其中FGF2含有一个由17个氨基酸组成的FGF受体结合域,能够与特定的FGF受体结合进行信号的转导。在细胞层面,相比于空白对照组(C),低氧组(H)和低氧预适应组(HPC)FGF2在mRNA水平和蛋白水平的表达均有所下降(P＜0.05),而与H组相比,HPC组FGF2 mRNA水平和蛋白水平的表达有所升高(P＜0.05)。结论: FGF参与低氧预适应的神经保护作用。     

Interleukin-1 is associated with inflammation and structural lung disease in young children with cystic fibrosis

Background

Little is known about the role of interleukin (IL)-1 in the pathogenesis of cystic fibrosis (CF) lung disease. This study investigated the relationship between IL-1 signalling, neutrophilic inflammation and structural lung changes in children with CF.

Functional morphology of the respiratory organs of the air-breathing fish with particular emphasis on the African catfishes, Clarias mossambicus and C. gariepinus

The evolution of air-breathing and transition from water to land were pivotal events that greatly determined the ecological diversification, the advances and the successes of animal life. During their relocation onto land, the so-called bimodal breathers were literally caught at the water-air interface. Among such animals are the diverse air-breathing bony fish. Such taxa, however, strictly do not constitute the so-called ‘bridging animals’, i.e., the inaugural animals that crossed from water to land, nor are they their direct progenitors. The pioneer transitional animals were the Devonian rhipidistian amphibians that possessed a primitive lung which acquired O₂ directly from air and discharged CO₂ back into the same. By having particular morphological and physiological adaptations for terrestrialness, the modern amphibious- and aquatic air-breathers are heuristic analogues of how and why animals relocated from water to land. It has generally been espoused that lack or dearth of O₂ in water, especially in the warm tropical one, was an elemental driver for adoption of air-breathing. There is, however, no direct causal relationship between the evolution of air-breathing and the shift onto land: the move onto land was a direct solution to the existing inimical respiratory conditions in water. This is evinced in the facts that: a) even after attaining capacity of air-breathing, an important preadaptation for life on land, some animals continued living in water while periodically accessing air, b) in the fish species that live in the well-oxygenated waters, e.g., torrential rivers, only few air-breathe and c) air-breathing has still evolved in freshwaters and seawaters, where levels of dissolved O₂ are sufficiently high. Here, the structure and function of the respiratory organs of the air-breathing fish are succinctly outlined. Two African catfishes, Clarias mossambicus and C. gariepinus are highlighted.