基于OCT技术的鼠皮肤激光热损伤修复过程的监测

采用Er:YAG激光(波长为2 940 nm,能量密度为:2.5 J/cm2单光斑,扫描次数为4)照射活体小白鼠皮肤,利用光学相干层析成像(optical coherence tomography,OCT)技术在活体小鼠上观察其皮肤组织在激光作用之前及作用之后光热损伤修复的整个过程,得到了激光光热作用下引起损伤的皮肤组织在此过程中皮肤光学特性参数的变化情况,发现皮肤修复过程中光学参数有显著差异,并分析了这些差异引起的原因,以揭示激光美容中并发症主要因素。     

基于光学相干层析成像技术的小鼠表皮厚度的无损测量及分析

光学相干层析成像技术(optical coherence tomography,OCT)在研究活体皮肤的表皮和真皮上层方面是一种很有潜力的手段.本文以小白鼠为研究对象,脱毛后,采用OCT系统对同一部位的小鼠皮肤在制作切片过程中(活体、离体、固定24 h后)进行成像跟踪,分别获得OCT强度图中第一强度峰到第一个波谷,以及第一、二强度峰之间的距离,比较两种结果和组织学的对应情况,并分析其原因,同时关注切片过程中各种物理、化学因素对皮肤各层厚度的影响,研究了OCT图像的各个反射峰与实际皮肤的结构之间联系.     

IPL作用下鼠皮形态改变的显微观察与初步分析

观察光子嫩肤(IPL)后鼠皮的形态学随时间的改变情况,如:表皮层、真皮层的增厚或变薄的情况。探讨IPL作用下,皮肤的表皮、真皮厚度变化与IPL在特定波长的能量密度的关系。以小白鼠作为研究对象,先去毛,用IPL在一定波长不同的能量密度照射活体小白鼠皮肤,分别在照射前、照射后,以及之后的1天,3天,7天应用激光共聚焦显微镜观察皮肤内部的结构,并对其不同的能量密度与照射前相比进行分析,讨论了真皮胶原蛋白在组织的修复过程的作用及其中的关键因素。     

532 nm和808 nm激光及其线偏振激光辐照人正常膀胱与膀胱癌组织光学特性

采用双积分球系统和光辐射测量技术的基本原理 ,以及运用生物组织的光学模型 ,研究了 5 32nm和80 8nm激光及其线偏振激光辐照人正常膀胱和膀胱癌组织的光学特性 .结果表明 :膀胱癌组织对同一波长的激光或其线偏振激光的衰减明显较正常膀胱组织的要大 ,膀胱癌组织对 5 32nm和 80 8nm激光的衰减均较其线偏振激光的要略大一些 .膀胱癌组织对 5 32nm和 80 8nm激光及其线偏振激光的衰减明显较正常膀胱组织的要大 .正常膀胱或膀胱癌组织对同一波长的激光及其线偏振激光的折射率均没有明显的差异 ,膀胱癌组织对 5 32nm和80 8nm激光的折射率比正常膀胱的明显要大 .Kubelka Munk二流模型下 ,两种组织对同一波长的激光或其线偏振激光的光学特性均有显著性差异 (P <0 0 1) .同一组织对不同波长的激光及其线偏振激光的光学特性也有显著性差异 (P <0 0 1) ,正常膀胱组织对同一波长的激光及其线偏振激光的光学性有明显差异 ,而膀胱癌组织对同一波长的激光及其线偏振激光的光学特性则没有明显差异 .膀胱癌组织对 5 32nm和 80 8nm激光及其线偏振激光的前向散射通量i (x)、后向散射通量 j (x)、总散射通量I (x)的衰减均较正常膀胱组织的明显要大得多 ,且其i (x)均明显较j (x)要强     

强激光作用下生物组织光致破裂效应的研究

基于激光与生物组织作用时产生的光致破裂效应,利用脉冲激光直接聚焦于孕囊内的胚胎内部,激光产生的光致破裂效应对胚胎心脏造成损伤,造成胚胎的快速死亡,初步证明利用激光进行减胎手术有望成为一种新方法。采用输出波长1 064 nm、脉宽8 ns、单脉冲能量60～96 mJ可调的脉冲激光作用于牛肌肉组织样品,并用光学相干层析成像(OCT)系统测量实验样品的损伤直径和损伤深度,建立了不同的激光参数与被作用样品的损伤直径及损伤深度之间的关系。得出结论:样品的损伤深度和损伤直径与激光的脉冲能量成正相关关系,而与激光的脉冲频率成负相关关系。这对于激光应用于减胎手术时参数的优化和精确控制起到一定的指导作用。     

脉冲CO2激光骨组织消融和电钻磨削的弹坑形态比较

激光消融技术在生物骨硬组织领域具有广泛的应用前景.选用脉冲CO2激光对离体牛胫骨组织进行消融,以电钻作为参照组,体视显微镜和扫描电子显微镜观察骨组织弹坑的形态学变化,光学相干层析成像(OCT)技术测量弹坑消融深度.比较结果表明:脉冲CO2激光辐照骨硬组织后产生的消融凹陷在几何形状和形态学方面与电钻的磨削效果相类似.此外,喷水速率为31 mL/min时可减少热损伤,并提高消融效率.     

全光学光声/OCT双模态成像系统及其应用

本文提出了一种新型的全光学光声/OCT双模态成像系统。该系统利用同一个低相干迈克尔逊干涉仪即可实现非接触式光声成像和OCT于一体,系统装置结构简单,可同时获取生物组织的吸收与散射结构信息。通过模拟实验证明了该双模态成像系统的可行性及成像能力,并对活体小鼠耳朵同时进行光声/OCT成像测试,实验结果表明非接触式光声/OCT双模态成像系统可以实现生物组织内的微血管及散射结构的高分辨率成像。进一步地,我们将光声/OCT双模态成像系统应用于基底细胞癌的检测中,获得了初步的研究结果,表明了该系统在皮肤肿瘤诊断中的具有潜在的应用价值。     

基于光学相干层析成像技术的鼠皮肤II度烫伤及其修复过程监控

建立小鼠皮肤的Ⅱ度烫伤的模型,分别于烫伤前、烫伤后1 min、8 h、1 d、3 d、5 d、7 d、9 d、11 d、13 d、15 d、17 d,用光学相干层析成像技术(OCT)对烫伤的创面进行动态的监测,同时对创面进行组织病理学的检测,对结果进行分析。利用OCT单次散射模型获得皮肤在烫伤前后光衰减系数的变化情况,结果显示光衰减系数的值在烫伤后是呈先减小后增大的趋势,待修复完全后又恢复到烫伤前相近的值。该结果与组织病理学的结果相吻合,这表明OCT技术可以用于实时诊断烫伤的皮肤。     

皮肤的光学模型

基于人体皮肤的组织结构,光在皮肤组织中的传输特性以及皮肤各层的组织光学参数,建立了正常皮肤的光学模型,介绍了该模型中的组织光学参数的确定方法。本文建立的皮肤组织光学模型及其方法,可应用于皮肤光学基础与临床的其它研究中。     

OCT于大鼠脱水组织中光散射特性的分析研究

目的:探讨活体组织液体含量的改变对OCT成像的影响,以期提高OCT在诊断组织病理性质方面的能力。方法:实验中复制脱水大鼠病理模型,应用光学相干层析成像设备,进行大鼠舌浅表组织在体显微成像检测,并对图像中组织的信号衰减特性进行量化分析。结果:正常对照组大鼠体重明显增加,病理模型组显著下降,病理模型组于脱水3天和5天后组织的平均OCT信号衰减系数明显高于正常对照组(P<0.01),且5天较3天的病理模型组组织的信号衰减系数变化尤其显著(P<0.01)。结论:改变组织含液量,可显著改变OCT成像效果,且通过对OCT图像中信号的衰减系数分析,可获得组织细微的散射变化,从而有望提高OCT技术在组织性质方面的诊断能力。     

In vivo monitoring the dynamic process of acute retinal hemorrhage and repair in zebrafish with spectral‐domain optical coherence tomography

Retina, the only light sensor in the human eye, is hidden and extremely fragile. Optimized animal models and efficient imaging techniques are very important for the study of retinopathy. In this work, the rapid retinal injury process and the long‐term retinal repair process were in vivo continuously evaluated with a novel imaging technology spectral‐domain optical coherence tomography (SD‐OCT) in a unique animal model zebrafish. Acute retinal injury was constructed on adult zebrafish by needle injection surgery. SD‐OCT imaging was carried out immediately after the mechanical injury. The retinal hemorrhage, which lasted only 5 seconds, could be visualized dynamically by SD‐OCT. The process of blood clearance and retinal repair was also evaluated because SD‐OCT imaging is nondestructive. Both SD‐OCT imaging results and behavioral analyzing results demonstrated that zebrafish retina could be repaired by itself within 15 days, which was confirmed by the results of pathological experiment.     

Octreotide: a new approach to the management of acute abdominal hypertension

Acutely increased intra-abdominal pressure (IAP) may lead to abdominal compartment syndrome (ACS), which ischaemia/reperfusion (I/R) injury plays an important role. The main goal of the management of ACS is to lower the intra-abdominal pressure despite reperfusion injury. Octreotide (OCT), a synthetic somatostatin analogue, lowers the splanchnic perfusion. The aim of this study was to investigate whether OCT improves the reperfusion injury after decompression of acute abdominal hypertension.Under anesthesia, a catheter was inserted intraperitoneally and using an aneroid manometer connected to the catheter, IAP was kept at 20 mmHg (ischemia group; I) for 1h. In the I/R group, pressure applied for an hour was decompressed and 1h reperfusion period was allowed. In another group of I/R, OCT was administered (50 microg/kg i.p.) immediately before the decompression of IAP. The results demonstrate that kidney and lung tissues of malondialdehyde (MDA; an end product of lipid peroxidation) levels and myeloperoxidase (MPO; index of tissue neutrophil infiltration) activity were elevated, while glutathione (GSH; a key to antioxidant) levels were reduced in I/R group (P<0.001). Moreover, OCT treatment applied in the I/R group reduced the elevations in blood urea nitrogen (BUN) and serum creatinine levels. Our results implicate that IAP causes oxidative organ damage and OCT, by reducing splanchnic perfusion and controlling the reperfusion of abdominal organs, could improve the reperfusion-induced oxidative damage. Therefore, its therapeutic role as a "reperfusion injury-limiting" agent must be further elucidated in IAP-induced abdominal organ injury.     

VEGF-C attenuates renal damage in salt-sensitive hypertension

Salt-sensitive hypertension is a major risk factor for renal impairment leading to chronic kidney disease. High-salt diet leads to hypertonic skin interstitial volume retention enhancing the activation of the tonicity-responsive enhancer-binding protein (TonEBP) within macrophages leading to vascular endothelial growth factor C (VEGF-C) secretion and NOS3 modulation. This promotes skin lymphangiogenesis and blood pressure regulation. Whether VEGF-C administration enhances renal and skin lymphangiogenesis and attenuates renal damage in salt-sensitive hypertension remains to be elucidated. Hypertension was induced in BALB/c mice by a high-salt diet. VEGF-C was administered subcutaneously to high-salt-treated mice as well as control animals. Analyses of kidney injury, inflammation, fibrosis, and biochemical markers were performed in vivo. VEGF-C reduced plasma inflammatory markers in salt-treated mice. In addition, VEGF-C exhibited a renal anti-inflammatory effect with the induction of macrophage M2 phenotype, followed by reductions in interstitial fibrosis. Antioxidant enzymes within the kidney as well as urinary RNA/DNA damage markers were all revelatory of abolished oxidative stress under VEGF-C. Furthermore, VEGF-C decreased the urinary albumin/creatinine ratio and blood pressure as well as glomerular and tubular damages. These improvements were associated with enhanced TonEBP, NOS3, and lymphangiogenesis within the kidney and skin. Our data show that VEGF-C administration plays a major role in preserving renal histology and reducing blood pressure. VEGF-C might constitute an interesting potential therapeutic target for improving renal remodeling in salt-sensitive hypertension.     

In vivo electrical impedance spectroscopic monitoring of the progression of radiation-induced tissue injury.

This study evaluates the potential of electrical impedance spectroscopy (EIS) as a noninvasive technique for tracking the progression of radiation-induced damage in normal muscle tissue. Male Sprague-Dawley rats were irradiated locally to the gastrocnemius and biceps femoris muscle. Single doses were administered using a procedure that spares skin and bone. Complex impedance spectral measurements (taken at 50 frequency points between 1 kHz and 1 MHz) were made at monthly intervals using recessed disk electrodes applied to the skin. A histological scoring scheme was developed for evaluation of injury. A strong dose-dependent progression of injury evident in both spectral measurements and histological scoring has been observed. Latent time also appears to be dependent on dose with changes induced by 70 Gy evident by 2 months, changes induced by 90 Gy observed by 1 month, and dramatic changes found within 3 weeks at 150 Gy. Injury was morphologically comparable to the type of damage that occurs in response to small, fractionated doses, but on a much shorter time scale. Increased spectral shift was a consistent indicator of the extent of tissue injury at the time of measurement. The use of a large single dose resulted in an excellent model in terms of inducing a significant progression in tissue injury over a short post-treatment follow-up period in the muscle mass while also providing a consistent location for in vivo electrical impedance measurements. The results show that EIS can follow radiation-induced tissue change, suggesting that EIS has the potential to monitor the types of injury observed in late radiation damage of muscle tissue noninvasively.     

Two optical coherence tomography systems detect topical gold nanoshells in hair follicles,sweat ducts and measure epidermis

Optical coherence tomography (OCT) is an established imaging technology for in vivo skin investigation. Topical application of gold nanoshells (GNS) provides contrast enhancement in OCT by generating a strong hyperreflective signal from hair follicles and sweat glands, which are the natural skin openings. This study explores the utility of 150 nm diameter GNS as contrast agent for OCT imaging. GNS was massaged into skin and examined in four skin areas of 11 healthy volunteers. A commercial OCT system and a prototype with 3 μm resolution (UHR‐OCT) were employed to detect potential benefits of increased resolution and variability in intensity generated by the GNS. In both OCT‐systems GNS enhanced contrast from hair follicles and sweat ducts. Highest average penetration depth of GNS was in armpit 0.64 mm ± SD 0.17, maximum penetration depth was 1.20 mm in hair follicles and 15 to 40 μm in sweat ducts. Pixel intensity generated from GNS in hair follicles was significantly higher in UHR‐OCT images (P = .002) and epidermal thickness significantly lower 0.14 vs 0.16 mm (P = .027). This study suggests that GNSs are interesting candidates for increasing sensitivity in OCT diagnosis of hair and sweat gland disorders and demonstrates that choice of OCT systems influences results.      

Multiparametric,Longitudinal Optical Coherence Tomography Imaging Reveals Acute Injury and Chronic Recovery in Experimental Ischemic Stroke

Progress in experimental stroke and translational medicine could be accelerated by high-resolution in vivo imaging of disease progression in the mouse cortex. Here, we introduce optical microscopic methods that monitor brain injury progression using intrinsic optical scattering properties of cortical tissue. A multi-parametric Optical Coherence Tomography (OCT) platform for longitudinal imaging of ischemic stroke in mice, through thinned-skull, reinforced cranial window surgical preparations, is described. In the acute stages, the spatiotemporal interplay between hemodynamics and cell viability, a key determinant of pathogenesis, was imaged. In acute stroke, microscopic biomarkers for eventual infarction, including capillary non-perfusion, cerebral blood flow deficiency, altered cellular scattering, and impaired autoregulation of cerebral blood flow, were quantified and correlated with histology. Additionally, longitudinal microscopy revealed remodeling and flow recovery after one week of chronic stroke. Intrinsic scattering properties serve as reporters of acute cellular and vascular injury and recovery in experimental stroke. Multi-parametric OCT represents a robust in vivo imaging platform to comprehensively investigate these properties.     

Post-infarct cardiac injury,protection and repair:roles of non-cardiomyocyte multicellular and acellular components

Following myocardial infarction(MI), cardiomyocytes and infarct size are the focus of our attention when evaluating the extent of cardiac injury, efficacy of therapies or success in repairing the damaged heart by stem cell therapy. Numerous interventions have been shown by pre-clinical studies to be effective in limiting infarct size, and yet clinical trials designed accordingly have yielded disappointing outcomes. The ultimate goal of cardiac protection is to limit the adverse cardiac remodeling. Accumulating studies have revealed that post-infarct remodeling can be attenuated without infarct size limitation. To reconcile this, one needs to appreciate the significance of various cellular and acellular myocardial components that, like cardiomyocytes, undergo significant damage and dysfunction, which impact the ultimate cardiac injury and remodelling. Microvascular injury following ischemia-reperfusion may influence infarct size and promote inflammation. Myocardial injury evokes innate immunity with massive inflammatory infiltration that, although essential for the healing process, exacerbates myocardial injury and damage to extracellular matrix leading to dilative remodeling. It is also important to consider the multiple non-cardiomyocyte components in evaluating therapeutic efficacy. Current research indicates the pivotal role of these components in achieving cardiac regeneration by cell therapy. This review summarizes findings in this field, highlights a broad consideration of therapeutic targets,and recommends cardiac remodeling as the ultimate target.