Experimental study on the treatment of rabbit corneal melting after alkali burn with Collagen cross-linking

AIM: To evaluate the effect of Collagen cross-linking on the prevention of melting in rabbit corneas after alkali burn. METHODS: Twenty New Zealand white rabbits were randomly divided into model control group and collagen cross-linking treatment group. The second group of rabbits received collagen cross linked treatment. Both groups were applied with antibiotic eye drops to prevent infection. The corneas were evaluated for melting, opacity, pathological and immunohistochemistry, record the changes when 28 days after the animals were killed. RESULTS: In the control group, 6 out of 8 rabbits showed corneal melting after injury (14 +/- 4) days, while two corneal perforated. In collagen cross-linking treatment group, one rabbit showed corneal melting after injury 23 days, without corneal perforation; corneal dissolution rate between the two groups was significantly different (P <0.05). Pathological examination suggested that in the treatment group, mild corneal edema, mild damage to collagen fibers, inflammatory cell infiltration was significantly less than the control group. Immunohistochemistry showed that corneal collagen fibers arranged in neat rows in the control group. CONCLUSION: Collagen cross-linking treatment not only can prevent and delay the corneal melting after alkali burn, but also can reduce the destruction of corneal collagen fibers and infiltration of inflammatory cells in the corneal tissue.

Effects of AMD3100 subconjunctival injection on alkali burn induced corneal neovascularization in mice

AIM: To investigate the therapeutic effects of local and systemic administration of AMD3100 for alkali burn induced corneal neovascularization (CNV) in mice. METHODS: CNV was induced in vivo by alkaline burn of cornea in C57BL/6 mice. AMD3100 was administrated topically by subconjunctival injection or systemically by intraperitoneal injection for 7 days; balanced salt solution was administrated topically or systemically as a control respectively. Inflammatory index was evaluated by slit-lamp biomicroscopy and inflammatory cells infiltrated to cornea tissue were detected by histologic analysis at multiple time points. CNV was compared between the local and systemic treated mice 2 weeks after alkali burn, as quantified by CD34 immunostaining. Fluorescence-Activated Cell Sorter Analysis was used to investigate the mobilizing effects of EPC in mice after subconjunctival injected or intraperitoneal injected AMD3100. Immunohistochemistry was used to detect the expression of endothelial progenitor cells (EPC) marker proteins VEGFR2 and CD34. RESULTS: Three days after alkali burn, infiltration of inflammatory cells was found in corneal tissue. At the first 7 days of local injection group, the number of inflammatory cells was significantly lower than that in systemic injection group. CNV could be seen at the 7(th) day, and at the 14(th) day reached the peak, then started to decrease. The number of CNV in the subconjunctival injection group was 7.57 +/- 1.26 per 0.034mm(2), compared to a number of 14.87 +/- 2.21 per 0.034mm(2) in the control group (P<0.05). On the contrary, the number of CNV in the intraperitoneal injection group was a little higher than that in the control group, 16.34 +/- 1.53 per 0.034mm(2) vs 13.26 +/- 1.87 per 0.034mm(2). The research also showed that intraperitoneally, but not subconjunctivally injected AMD3100 could mobilize EPC. On the other hand, subconjunctival, but not intraperitoneally injected AMD3100 could reduce the expression of EPC marker proteins. CONCLUSION: In mice locally administrated AMD3100 can reduce the number of alkali burn induced CNV. The number of inflammatory cells and inflammatory responses in corneal tissue.

Efficacy of the nucleotide-binding oligomerization domain 1 inhibitor Nodinhibit-1 on corneal alkali burns in rats

AIM: To evaluate the therapeutic effect of Nodinhibit-1 on alkali-burn-induced corneal neovascularization (CNV) and inflammation. The nucleotide-binding oligomerzation domain 1 (NOD1) is a potent angiogenic gene. METHODS: The alkali -burned rat corneas (32 right eyes) were treated with eye drops containing Nodinhibit-1 or phosphate buffered solution (PBS, pH 7.4) only, four times per day. CNV and inflammation were monitored using slit lamp microscopy, and the area of CNV was measured by formula. Vascular endothelial growth factor (VEGF) and pigment epithelium -derived factor (PEDF) was determined by Western blot analysis. The TUNEL assay was used to assess the corneal apoptosis cells. RESULTS: Alkali-burn-induced progressive CNV and inflammation in the cornea. After treatment for 7d and 14d, there were statistically significant differences in the CNV areas and inflammatory index on that between two group(P<0.05, respectively). Epithelial defect quantification showed a significant difference between the two groups at days 4 and 7 after the alkali burns (P<0.05). The apoptotic. cells on days 1, 4, and 7 between the two groups showed significant differences at all time points (P<0.05, respectively). Compared to that in control group, the protein level of VEGF expression was significantly reduced whereas the PEDF expression was increase in the Nodinhibit-1 groups on day 14(P<0.05, respectively). CONCLUSION: Topical application of 10.0 mu g/mL Nodinhibit -1 may have potential effect for the alkali burn -induced CNV and inflammation. The effect of Nodinhibit -1 on CNV may be by regulation the equilibrium of VEGF and PEDF in the wounded cornea.

Effect of nintedanib thermo-sensitive hydrogel on neovascularization in alkali burn rat model

AIM:To investigate the effects of nintedanib thermo-sensitive hydrogel(NTH)on neovascularization and related markers in corneal alkali burns of Wistar rats.METHODS:NTH was prepared by grinding,and its phase-transition temperature was determined.Thirty specific-pathogen-free Wistar rats served as a model of corneal alkali burn in the right eye were randomly divided into 3 groups(n=10,each):model group treated with 0.9%saline once a day,NTH group with 0.2%nintedanib b.i.d,and dexamethasone group with dexamethasone ointment once a day.The left eye of rats served as the controls.The corneal transparency was observed under a slit-lamp microscope,and the area of neovascularization was calculated.On day 7,the rats were sacrificed,and the cornea was removed and embedded with paraffin,then stained with hematoxylin一eosin,and the expression of vascular endothelial growth factor receptor 2(VEGFR-2)and CD31 in the corneal tissues of each group was detected by immunofluorescence.RESULTS:The phase-transition temperature ofnintedanib obtained by grinding was 37℃after adding artificial tears.The results of the alkali burn model indicated that the growth rate of neovascularization in the NTH group was slower than that in the model group,and the neovascularization area was significantly smaller than that in the model group(P<0.05).Moreover,CD31 and VEGFR-2 expression levels in the NTH group were significantly lower than those in the model group.CONCLUSION:NTH becomes colloidal at body temperature,which is beneficial for releasing the drug slowly and can significantly inhibit the neovascularization of corneal induced by alkali burn in rats.

Research on mouse model of grade Ⅱ corneal alkali burn

AIM： To choose appropriate concentration of sodium hydroxide（Na OH） solution to establish a stable and consistent corneal alkali burn mouse model in grade II.·METHODS： The mice（n =60） were randomly divided into four groups and 15 mice each group. Corneal alkali burns were induced by placing circle filter paper soaked with Na OH solutions on the right central cornea for 30 s.The concentrations of Na OH solutions of groups A, B, C,and D were 0.1 mol/L, 0.15 mol/L, 0.2 mol/L, and 1.0 mol/L respectively. Then these corneas were irrigated with 20 m L physiological saline（0.9% Na Cl）. On day 7 postburn, slit lamp microscope was used to observe corneal opacity,corneal epithelial sodium fluorescein staining positive rate, incidence of corneal ulcer and corneal neovascularization, meanwhile pictures of the anterior eyes were taken. Cirrus spectral domain optical coherence tomography was used to scan cornea to observe corneal epithelial defect and corneal ulcer.·RESULTS： Corneal opacity scores（ x ±s） were not significantly different between the group A and group B（P =0.097）. Incidence of corneal ulcer in group B was significantly higher than that in group A（P =0.035）.Incidence of corneal ulcer and perforation rate in group B was lower than that in group C. Groups C and D had corneal neovascularization, and incidence of corneal neovascularization in group D was significantly higher than that in group C（P =0.000）.·CONCLUSION： Using 0.15 mol/L Na OH can establish grade II mouse model of corneal alkali burns.

Evaluation of immersion 20 MHz B-scan ultrasonography in observing lens in the alkali burn eyes

·AIM: To evaluate the accuracy of 20 MHz immersion Bscan ultrasonography in observing lens and to investigate the value of this noninvasive preoperative diagnosis method in alkali burn eyes.·METHODS: It was a comparative study. Fifty-six cases(56 eyes) of alkali burn eyes were examined by ultrasound biomicroscopy(UBM) and immersion 20 MHz B-scan ultrasonography from June 2011 to April 2013,the images were analyzed, and the ultrasonographic diagnosis compared with the operation results.·RESULTS: In 56 alkali burn eyes examined by UBM, the lens were not detected in 16 eyes; the IOL could be detected in 2 eyes; the anterior lens capsule surface or/and the front lens could be detected in 18 eyes, and lens opacification in 3 eyes of them; suspected abnormal lens were detected in the other 20 eyes. In all the same eyes examined by immersion 20 MHz B-scan ultrasonography,the lens were not detected in 16 eyes; the IOL could be detected in 2 eyes; 24 abnormal lens(opacity, lens expansion, shrinkage) and 14 normal lens were found.Compared with the intraoperative findings, the diagnostic accordance rate of the immersion 20 MHz B-scan appearance of lens was 100%(56/56), which was significantly higher than examined by UBM 57.14%(32/56)(χ2=30.55, P =0.0000).·CONCLUSION: Immersion 20 MHz B-scan ultrasonography can observe the lens accurately in alkali burn eyes. It has important clinical value to combine with UBM in eyes of alkali burn.

The Effect of Fibronectin on Re-epithelialization of Rabbits Cornea after Alkali Burn

The authors found experimentally that (1) fibronectin enhanced the healing of rabbit corneal epithelium after alkali burn and prevented the secondary breakdown; (2) it rapidly deposited on the denuded basement membrane to disappear as epithelial cells slided over, and (3) ultrastructurally, the neighbouring epithelial cells became flattened, with filopodia at the advancing edge, and extended to the wounded areas at 24 hours after the burn. However, the epithelial defects recurred 72 hours after the burn...

LRG1 promotes corneal angiogenesis and lymphangiogenesis in a corneal alkali burn mouse model

AIM:To investigate the potential effect and mechanism of leucine-richα-2-glycoprotein-1(LRG1)on corneal angiogenesis and lymphangiogenesis.METHODS:Corneal neovascularization and lymphatics were induced by establishing alkali burn mouse model.Immunofluorescence staining was performed to detect the location of LRG1 in cornea tissues and to verify the source of LRG1-positive cells.Corneal whole-mount staining for CD31(a panendothelial cell marker)and lymphatic endothelial hyluronan receptor-1(LYVE-1;lymphatic marker)was performed to detect the growth of blood and lymphatic vessels after local application of exogenous LRG1 protein or LRG1 si RNA.In addition,expressions of the proangiogenic vascular endothelial growth factor(VEGF)related proteins were detected using Western blot analysis.RESULTS:LRG1 was dramatically increased in alkali burned corneal stroma in both the limbal and central areas.LRG1-positive cells in the corneal stroma were mainly derived from Vimentin-positive cells.Local application ofexogenous LRG1 protein not only aggravated angiogenesis but also lymphangiogenesis significantly(P<0.01).LRG1 group upregulated the levels of VEGF and the vascular endothelial growth factor receptor(VEGFR)family when compared with the phosphate-buffered saline(PBS)control group.We also found that LRG1-specific si RNA could suppress corneal angiogenesis and lymphangiogenesis when compared with the scramble si RNA-treated group(P<0.01).CONCLUSION:LRG1 can facilitate corneal angiogenesis and lymphangiogenesis through heightening the stromal expression of VEGF-A,B,C,D and VEGFR-1,2,3;LRG1-specific si RNA can suppress corneal angiogenesis and lymphangiogenesis in corneal alkali burn mice.

Emodin suppresses alkali burn-induced corneal inflammation and neovascularization by the vascular endothelial growth factor receptor 2 signaling pathway

OBJECTIVE:To investigate the effects of emodin on alkali burn-induced corneal inflammation and neovascularization.METHODS:The ability of emodin to target vascular endothelial growth factor receptor 2(VEGFR2)was predicted by molecular docking.The effects of emodin on the invasion,migration,and proliferation of human umbilical vein endothelial cells(HUVEC)were determined by cell counting kit-8,Transwell,and tube formation assays.Analysis of apoptosis was performed by flow cytometry.CD31 levels were examined by immunofluorescence.The abundance and phosphorylation state of VEGFR2,protein kinase B(Akt),signal transducer and activator of transcription 3(STAT3),and P38 were examined by immunoblot analysis.Corneal alkali burn was performed on 40 mice.Animals were divided randomly into two groups,and the alkali-burned eyes were then treated with drops of either 10μM emodin or phosphate buffered saline(PBS)four times a day.Slitlamp microscopy was used to evaluate inflammation and corneal neovascularization(CNV)in all eyes on Days 0,7,10,and 14.The mice were killed humanely 14 d after the alkali burn,and their corneas were removed and preserved at-80℃ until histological study or protein extraction.RESULTS:Molecular docking confirmed that emodin was able to target VEGFR2.The findings revealed that emodin decreased the invasion,migration,angiogenesis,and proliferation of HUVEC in a dose-dependent manner.In mice,emodin suppressed corneal inflammatory cell infiltration and inhibited the development of corneal neovascularization induced by alkali burn.Compared to those of the PBS-treated group,lower VEGFR2 expression and CD31 levels were found in the emodintreated group.Emodin dramatically decreased the expression of VEGFR2,p-VEGFR2,p-Akt,p-STAT3,and p-P38 in VEGF-treated HUVEC.CONCLUSION:This study provides a new avenue for evaluating the molecular mechanisms underlying corneal inflammation and neovascularization.Emodin might be a promising new therapeutic option for corneal alkali burns.

Effect of vasoactive intestinal peptide on the wound healing of alkali-burned corneas

AIM： To study the effect of vasoactive intestinal peptide （VIP） on wound healing in experimental alkali burns of the cornea. METHODS： Twenty-seven albino rabbits, weighing 3.2 -0.75 kg were used. Alkali burns were induced on corneas by applying 10 mm Whatman paper No：50 soaked in 1 mol/L NaOH. They have further classified into 5 groups as follows： 1） control group given no treatment （n=5）; 2） VIP given subconjunctivally （n=6）; 3） VIP injected into anterior chamber （n=6）; 4） NaCI 0.9% given subconjunctivally （n=5）; 5） NaCI 0.9% given into the anterior chamber （n=5）. All treatment protocols except control group were followed by topical eye drops composed of VIP at two hourly intervals for one week from 8 a.mo to 6 p.m, RESULTS： VIP treated groups of rabbits with alkali burns were found to have better wound healing findings histo-pathologically when compared to those of control group who have received no treatment on day 30. No differences were observed between groups in respect to degree of polymorphonuclear leukocytes （PMNL） infiltration and degree of loss of amorphous substrate on day 15. However, PMNL infiltration and degree of loss of amorphous substrate were lower in Groups 2 and 3 when compared to that of control group on day 30 （P〈0.05）. CONCLUSION： We have shown that VIP has positive effects on alkali induced corneal burns. VIP may inhibit PMNL migration to cornea through an immunomodulatory effect. Inhibition of PMNL migration might reduce the release of collagenaees and this might prevent the extracellular amorphous substance loss.

Observation on ultrastructure and histopathology of cornea following femtosecond laser-assisted deep lamellar keratoplasty for acute corneal alkaline burns

AIM： To demonstrate the changes in ultrastructure and histopathology of the cornea in acute corneal alkaline burns after femtosecond laser-assisted deep lamellar keratoplasty.·METHODS： The New Zealand white rabbits treated with alkaline corneal burn were randomized into two groups,Group A（16 eyes） with femtosecond laser-assisted deep lamellar keratoplasty 24 h after burn and Group B（16 eyes）without keratoplasty as controls. All eyes were evaluated with transmission electron microscopy（TEM） at 1, 2, 3,and 4wk follow-up, then all corneas were tested by hematoxylin and eosin staining histology.· RESULTS： The corneal grafts in Group A were transparent, while those in Group B showed corneal stromal edema and loosely arranged collagen fibers. One week after treatment, TEM revealed the intercellular desmosomes in the epithelial layers and intact non-dissolving nuclei in Group A. At week 4, the center of the corneas in Group A was transparent with regularly arranged collagen fibers and fibroblasts in the stroma. In Group B, squamous cells were observed on the corneal surface and some epithelial cells were detached.· CONCLUSION： Femtosecond laser-assisted deep lamellar keratoplasty can suppress inflammatory responses, prevent toxic substance-induced injury to the corneal endothelium and inner tissues with quicker recovery and better visual outcomes.

Hydrogen promotes the activation of Cu, Zn superoxide dismutase in a rat corneal alkali-burn model

AIM: To investigate the effects of hydrogen(H2) on Cu, Zn superoxide dismutase(SOD1) activation in a rat model of corneal alkali burn. METHODS: In each rat, one cornea was subjected to alkali exposure. Physiological saline(saline group) or H2-dissolved saline(H2 group) was instilled continuously on the cornea for 5 min before and after alkali exposure. Inflammatory cells, neovascularization, and cytoplasmic SOD1 levels were evaluated immunohistochemically in enucleated eyes from both groups. Three-dimensional ultrastructural tissue changes in the eyes were analyzed using low-vacuum scanning electron microscopy.RESULTS: The numbers of both inflammatory and vascular endothelial cells were significantly reduced in the corneas of the H2 group(P<0.01). Furthermore, H2 treatment increased both cytoplasmic SOD1 levels(P<0.01) and activity in corneal epithelial cells(P<0.01). Notably, the SOD1 activity level in the H2 group was approximately 2.5-fold greater than that in the saline group.CONCLUSION: H2 treatment suppresses inflammation and neovascularization in the injured cornea and indirectly suppresses oxidative insult to the cornea by upregulating the SOD1 enzyme protein level and activity.

某350 MW机组对冲锅炉燃用高碱煤炉膛腐蚀防治研究

为降低燃料采购成本,保证燃料供应,甘肃某电厂大比例掺烧了部分新疆高碱的广汇煤和新疆能源煤。高碱煤掺烧后,锅炉出现较严重的受热面高温腐蚀和结焦现象,负荷最高只能带到85%ECR。为减轻高温腐蚀,对锅炉开展了煤质特性、燃烧优化调整和设备改进技术研究。结果表明:锅炉燃用较低硫份煤的情况下仍然发生较严重的高温腐蚀,主要与新疆煤中的钠、钙等碱金属及氯质量分数较高有关,通过提高氧量、降低一次风量、减弱燃烧器外二次风旋流强度和开大贴壁风等运行调整手段,可以一定程度上改善水冷壁高温腐蚀特性;彻底解决该问题,还需使用添加剂、进行防高温腐蚀喷涂、增加吹灰器、改进贴壁风和燃烧器设计等技术途径。该研究成果可为解决高碱煤掺烧过程中出现类似问题的电厂提供借鉴和参考。

生物材料促进角膜碱烧伤修复的作用机制和应用途径

背景:在角膜碱烧伤治疗中,传统治疗方法存在多种局限,尤其在控制炎症、预防新生血管形成和抑制角膜瘢痕化方面表现不佳。天然材料、合成材料或复合材料为治疗提供了多元化的选择,然而生物材料促进角膜碱烧伤修复的相关机制尚未形成系统深入的认识。目的:对目前生物材料促进角膜碱烧伤修复的国内外研究进行梳理,综述生物材料修复角膜碱烧伤的机制及其应用途径。方法:第一作者以“角膜,碱烧伤,羊膜,透明质酸,胶原,壳聚糖,高分子材料”“Amniotic membrane,Hyaluronic acid,Collagen,Chitosan,Polymer,Cornea,Alkali burn”为关键词在Pub Med、Web of Science、中国知网和万方文献数据库内检索,根据纳入标准和排除标准,最终纳入符合要求的76篇文献进行综述。结果与结论:(1)在角膜碱烧伤修复领域,羊膜、透明质酸、胶原、壳聚糖和可降解高分子材料等生物材料被广泛研究和应用,这些生物材料各有其特点和优缺点,在不同方面都有所突出。(2)首先,羊膜因含丰富的生物活性因子而被认为是最有前景的生物材料之一,其生物相容性良好,并且能够调节角膜炎症反应,但是存在供体短缺和易感染疾病的问题。(3)透明质酸具有良好的保湿性和生物相容性,并且能够提高角膜细胞的生存率和增加角膜透明度。(4)胶原具有良好的生物相容性和支架结构,能够促进角膜细胞的黏附和增殖,促进角膜组织结构的重建。(5)壳聚糖具有良好的生物相容性和可降解性,可作为载体用于药物递送和细胞移植。(6)可降解高分子材料具有较好的降解可控性,可为角膜碱烧伤的修复提供良好的支持和递送平台,但其稳定性和生物相容性仍需进一步研究。(7)综合来看,目前还没有一种生物材料能够完全解决角膜碱烧伤的修复问题,每种生物材料都有其特定的适用场景和局限性。(8)未来的研究方向应该是通过进一步改进生物材料的性能和结构,探索更有效的组合应用方式,以及深入了解生物材料与角膜组织的相互作用机制,以提高角膜碱烧伤的治疗效果和患者的生活质量。

枸杞糖肽对角膜碱烧伤小鼠角膜炎症反应及愈合的作用及其机制研究

目的探讨枸杞糖肽(LbGp)在角膜碱烧伤损伤愈合中的作用及其机制。方法根据治疗方式不同将45只健康、SPF级、6~8周、雄性C57BL/6J小鼠随机分为正常对照组(N组)、损伤对照组(PBS组)、LbGp治疗组(LbGp组),每组15只。PBS组和LbGp组小鼠右眼复制碱烧伤模型,采用点眼联合结膜下注射的方式分别给予PBS溶液或LbGp溶液(10 mg/mL)治疗。治疗后第3天采用裂隙灯显微镜及HE染色观察各组小鼠角膜上皮修复情况和角膜组织结构;实时荧光定量聚合酶链反应、Western blotting及免疫组织化学染色技术检测各组小鼠角膜组织NOD样受体热蛋白结构域相关蛋白3(NLRP3)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、髓过氧化物酶(MPO)的表达及核转录因子κB(NF-κB)的磷酸化水平。治疗后的第14天采用裂隙灯显微镜对角膜混浊程度进行评分,HE染色观察角膜组织结构。结果治疗后第3天LbGp组小鼠角膜上皮愈合速度快于PBS组(P<0.05)。N组、PBS组及LbGp组的NF-κB-p65、NLRP3、IL-1β及IL-6基因和蛋白相对表达量比较,差异均有统计学意义(P<0.05),PBS组均高于N组(P<0.05),LbGp组均低于PBS组(P<0.05)。LbGp组角膜基质中MPO染色阳性的中性粒细胞的浸润较PBS组减轻。治疗后第14天LbGp组小鼠角膜混浊评分低于PBS组(P<0.05)。结论LbGp治疗可以抑制小鼠角膜碱烧伤后NF-κB的激活及NLRP3、IL-1β的表达,从而减轻过度的炎症反应,促进小鼠角膜上皮再生及角膜结构恢复,有助于恢复角膜的透明性和完整性。

双U型火焰液态排渣锅炉纯燃高碱煤热力计算及数值模拟研究

对液态排渣锅炉的深入研究将会推动纯燃高碱煤技术的推广。以一台超临界350 MW机组直流双U型火焰液态排渣锅炉为研究对象,以燃烧室、捕渣管束和冷却室为单元,从热平衡的角度出发展开热力计算,并借助数值模拟手段,研究了炉膛内设计工况下的流场、温度场和组分场及其在变负荷时的变化情况。热力计算和数值模拟表明,几处烟气温度结果偏差都低于40.0℃。燃烧室出口烟气温度偏差仅为1.2℃,冷却室出口烟气温度偏差为15.6℃。经过验证和比较,所采用的热力计算方法可以应用于双U型火焰液态排渣锅炉纯燃高碱煤热力计算。数值模拟结果显示,炉内空气动力场良好,旋流形成的回流区可以增加煤粉颗粒在燃烧室的运动路径,促进煤粉的燃尽。烟气在流经捕渣管时,温度大大降低,同时流场也受到了一定的扰动,可以有效捕捉灰渣。在变负荷工况下,炉内的速度场按负荷降低成比例下降,回流区的大小基本不变。炉内的温度水平降低,当给煤量由100%降至75%时,燃烧室出口烟温降低了约75℃,而冷却室出口烟温降低了约200℃。本研究可为双U型火焰液态排渣锅炉纯燃高碱煤提供参考。

石斛酚抑制碱烧伤大鼠角膜新生血管的实验研究

目的 探讨石斛酚抑制碱烧伤大鼠角膜新生血管(corneal neovascularization, CNV)的作用。方法 构建SD大鼠角膜碱烧伤模型,随机分成正常对照组、模型对照组、低浓度石斛酚组、高浓度石斛酚组、阿柏西普组,每组各10只。低浓度石斛酚组、高浓度石斛酚组、阿柏西普组分别于伤后第1天结膜下注射2.5 mg/0.05 mL、5 mg/0.05 mL石斛酚,2 mg/0.05 mL阿柏西普。伤后第3、7、14天,观察并计算角膜新生血管占全角膜面积的百分比、角膜混浊评分并测量角膜厚度。碱烧伤第14天,处死全部大鼠,通过苏木素-伊红(HE)染色和免疫组化观察角膜组织中VEGF和CD34蛋白表达水平,以及通过ELISA检测各组VEGF、IL-1β、TNF-α的蛋白含量。结果 碱烧伤后第7、14天,低浓度石斛酚组、高浓度石斛酚组、阿柏西普组角膜新生血管面积占全角膜面积百分比均显著低于模型对照组(所有P<0.05)。碱烧伤后第14天,高浓度石斛酚组角膜混浊评分显著小于模型对照组(P<0.05),模型对照组、低浓度石斛酚组角膜厚度均显著高于正常对照组(所有P<0.001)。但是,高浓度石斛酚组、阿柏西普组角膜厚度与正常对照组相比较,均无显著性差异(所有P>0.05)。此外,低浓度石斛酚组、高浓度石斛酚组、阿柏西普组角膜组织中VEGF、IL-1β、TNF-α蛋白表达均显著低于模型对照组(所有P<0.01)。结论 结膜下注射石斛酚对碱烧伤大鼠角膜新生血管有抑制作用,并能促进角膜水肿的吸收。

污泥掺烧工况下空预器的积垢成因分析及除垢方法研究

城市废水污泥作为低热值燃料与燃煤掺混进入锅炉燃烧,污泥与燃煤按照一定比例掺混不会影响锅炉的燃烧。污泥与燃煤的掺混使燃料的水分、灰分甚至硫分等成分发生了变化,燃烧后烟气成分也相应发生变化,空预器发生结垢堵塞现象的风险加剧。针对上海某电站锅炉在掺烧8%左右污泥空预器的结垢现象进行研究,通过对垢样的分析,发现结垢的垢样中含硫酸氢铵(NH_(4)HSO_(4))成分,硫酸氢铵黏性强,吸附飞灰形成较为坚硬的垢物。而硫酸氢铵的生成析出与烟气的三氧化硫(SO_(3))的浓度与氨(NH3)浓度比例,含水率及温度场相关,空预器提供的温度场正好满足硫酸氢铵的生成析出。依据结垢机理进行了阻垢和除垢的方法研究,确认投入钙碱中和烟气的三氧化硫,可降低硫酸氢铵的生成量,有效地缓减垢的生成。提高温度并投入钙碱,垢中的硫酸氢铵会与钙碱反应,生成硫酸钙(CaSO_(4))及气态氨和二氧化碳(CO_(2))等。黏性物质硫酸氢铵的解析后降低了垢的黏合度,同时反应后气态生成物还可起到疏松垢体作用,从而起到解垢的效果。

MiR-497对角膜新生血管的抑制作用及其靶向STAT3调控机制

目的探讨miR-497在碱烧伤诱导的角膜新生血管(CNV)形成过程中的作用及其机制。方法选用健康清洁级6~8周龄野生型(WT)C57BL/6小鼠42只以及成功鉴定为CRISPR/Cas9介导的miR-497敲除(KO)和过表达转基因(TG)小鼠各42只,分别作为WT组、KO组和TG组。构建角膜碱烧伤模型,分别于造模后第3、7、14、21天行裂隙灯显微镜检查并进行角膜上皮损伤评分和角膜基质混浊评分,测量CNV面积;采用组织病理染色法观察角膜结构变化和炎症细胞的表达;采用免疫组织化学染色法检测角膜组织中CD31的表达;采用荧光素酶报告基因检测miR-497与信号转导及转录激活蛋白3(STAT3)之间的靶向结合关系;采用实时荧光定量PCR法检测各时间点小鼠角膜组织中miR-497以及血管内皮生长因子A(VEGFA)、肿瘤坏死因子(TNF)-α、白细胞介素(IL)-6、IL-1β、单核细胞趋化蛋白(MCP)-1 mRNA的相对表达量变化;采用Western blot法检测各组造模后14 d角膜组织中STAT3、p-STAT3蛋白的表达。结果小鼠角膜碱烧伤后出现角膜损伤和炎症细胞浸润,同时出现CNV。角膜上皮损伤评分、角膜基质混浊评分和CNV面积呈现先升高后降低的趋势,并在造模后第14天时达峰值。各组造模后不同时间点角膜上皮损伤评分、角膜基质混浊评分、CNV面积和CD31阳性细胞数总体比较差异均有统计学意义(F_(分组)=49.19、34.56、44.56、77.56,均P<0.01;F_(时间)=51.62、65.62、71.32、46.12,均P<0.01);其中KO组各时间点角膜上皮损伤评分、角膜基质混浊评分、CNV面积和CD31阳性细胞数均高于WT组和TG组,TG组各指标均低于WT组,差异均有统计学意义(均P<0.05)。在野生型STAT3共转染细胞中,miR-497组荧光素酶活性明显低于miR-阴性对照组和正常对照组,差异有统计学意义(均P<0.05);在突变型STAT3转染细胞中,各组间荧光素酶活性比较,差异无统计学意义(F=0.69,P=0.56)。WT组、KO组、TG组造模后14 d角膜组织中miR-497的相对表达量分别为0.68±0.11、0.41±0.06、1.05±0.14,均明显低于造模前的1.00±0.04、0.56±0.07、1.34±0.11,差异均有统计学意义(均P<0.01)。造模后第14天,KO组STAT3及p-STAT3蛋白相对表达量均明显高于WT组和TG组,TG组各蛋白相对表达量低于WT组,差异均有统计学意义(均P<0.05)。各组造模后各时间点VEGFA、TNF-α、IL-6、IL-1β和MCP-1 mRNA相对表达量均明显高于造模前,KO组各mRNA相对表达量明显高于同时间点WT组和TG组,TG组各mRNA相对表达量明显低于同时间点WT组,差异均有统计学意义(均P<0.01)。结论MiR-497可抑制碱烧伤诱导的角膜炎症反应及CNV形成,其可能通过靶向STAT3抑制炎症信号通路的激活。

人脐带间充质干细胞移植治疗角膜碱烧伤的实验研究

目的:研究人脐带间充质干细胞(hUCMSCs)移植治疗兔角膜碱烧伤的疗效,分析多形核中性白细胞(PMNs)的浸润和血管内皮生长因子(VEGF)的表达变化。方法:将75只健康日本白兔随机分成A、B、C组,每组25只,均建立右眼角膜碱烧伤模型。A组兔右眼角膜碱烧伤后立即行角膜病灶区羊膜负载hUCMSCs覆盖术;B组兔右眼角膜碱烧伤后立即行角膜病灶区羊膜覆盖术;C组兔右眼角膜碱烧伤后未进行处理。角膜碱烧伤后3、7、14、21、28d,裂隙灯下观察实验兔角膜恢复情况并照相,对角膜新生血管(CNV)生长情况进行评分,并分离角膜组织制作病理切片,通过苏木素-伊红(HE)染色观察PMNs浸润情况,采用免疫组化染色法测定VEGF的表达。结果:角膜碱烧伤后14d时,A组CNV较B组生长明显缓慢,A组病灶区周围CNV生长评分明显低于B组(P<0.05)。碱烧伤后3d时,角膜PMNs数量增加,浸润角膜基质层,7d时稍有下降,14d时达到峰值,后渐进性下降,碱烧伤后早期浸润在病灶区角膜基质内,后期浸润范围与溃疡面积相同,碱烧伤后各时间点A组和B组角膜PMNs密度均明显低于C组(P<0.05),且14、21d时,A组均明显低于B组(P<0.05)。碱烧伤后各组角膜VEGF表达水平均在7~14d时达到峰值,28d时明显降低,碱烧伤后各时间点A组和B组VEGF表达水平均明显低于C组(P<0.05),且7、14、21d时,A组均明显低于B组(P<0.05)。结论:羊膜负载hUCMSCs移植治疗兔角膜碱烧伤可减少CNV形成,抑制碱烧伤后角膜血管化,角膜病理损伤及血管化与PMNs和VEGF密切相关。