Lipid distribution, composition and uptake in bovine articular cartilage studied using Raman micro-spectrometry and confocal microscopy.
Lipid distribution, composition and uptake in bovine articular cartilage studied using Raman micro-spectrometry and confocal microscopy.
复制标题
DOI：
10.1111/joa.12624
复制
发表时间：
2017-07
影响因子：
2.4
通讯作者：
Winlove CP
中科院分区：
文献类型：
--
作者：
Mansfield JC;Winlove CP
在显微镜下研究了新鲜牛关节软骨中内源性脂质的分布和组成以及外源性脂肪酸的转运。为了研究内源性脂质的分布和组成，在深层和浅层区域中拍摄软骨细胞及其周围基质的高光谱拉曼图。这些结果揭示了两个区域之间脂质分布和组成的差异。细胞外脂质在浅层细胞周围可见，但在深层细胞周围未见。此外，观察到细胞内的脂滴更大，更多的深区（P = 0.01）。 细胞外脂质主要是游离的饱和脂肪酸，而细胞内的脂滴含有甘油三酯与不饱和脂肪酸链。通过将软骨样品在含有荧光标记的棕榈酸酯的Dulbecco改良Eagle培养基中孵育一系列时间和温度来研究脂肪酸摄取和转运。孵育后，使用共聚焦显微镜对棕榈酸酯分布进行成像。棕榈酸盐仅在浅表区优先蓄积在区域基质中，其浓度是整体基质中浓度的100倍（P = 0.001）。 两个区域的软骨细胞对棕榈酸的摄取显示出不同的温度敏感性（P = 0.05），这将支持细胞通过主动和被动机制摄取棕榈酸的观点。 该研究揭示了软骨细胞在其脂质含量、细胞外脂质环境和获得外源性脂肪酸方面的浅表区和深层区之间的巨大差异。
The distribution and composition of endogenous lipids in articular cartilage and transport of exogenous fatty acids have been investigated on a microscopic scale in fresh bovine articular cartilage. To investigate the distribution and composition of the endogenous lipids, hyperspectral Raman maps were taken of chondrocytes and their surrounding matrix in both the deep and superficial zones. These revealed differences in both lipid distribution and composition between the two zones. Extracellular lipid was observed surrounding the cells in the superficial zone but not in the deep zone. Additionally, intracellular lipid droplets were observed that were larger and more numerous in the deep zone (P = 0.01). The extracellular lipid was primarily free saturated fatty acid, whereas the cellular lipid droplets contained triglycerides with unsaturated fatty acid chains. Fatty acid uptake and transport were investigated by incubating cartilage samples in Dulbecco's modified Eagle's medium containing fluorescently labelled palmitate for a range of times and temperatures. After incubation, the palmitate distribution was imaged using confocal microscopy. Palmitate accumulated preferentially in the territorial matrix only in the superficial zone where the concentration was up to 100‐fold greater than that in the bulk matrix (P = 0.001). Palmitate uptake by the chondrocytes in both zones showed differential temperature sensitivity (P = 0.05), which would support the idea that cells take up palmitate by both active and passive mechanisms. The study reveals large differences between chondrocytes in the superficial and deep zones in their lipid content, in their extracellular lipid environment and in their access to exogenous fatty acids.