Water diffusion in the rabbit lens in vivo.
Water diffusion in the rabbit lens in vivo.
复制标题
水在兔体内晶状体中的扩散。
DOI：
10.1159/000060821
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Cheng,Hong-Ming
中科院分区：
文献类型：
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作者：
Cheng,Hong-Ming
目的：观察兔体内晶状体和糖性白内障中水分的扩散。材料与方法：用磁共振成像（MRI）观察四氧嘧啶糖尿病兔和半乳糖血症兔晶状体皮层水分自扩散的变化。这些动物被安置在4.7特斯拉的动物系统中，并与1英寸的表面线圈一起用于眼睛。采用脉冲梯度自旋回波序列进行弥散加权MRI，主、次坐标梯度强度为0-6 Gs/cm。其他MRI参数TR（重复时间）/TE（回声时间）= 2000 /10ms，视场4 cm，矩阵256× 128。结果：水松弛增加，使正常兔晶状体赤道皮质深度/晶状体长轴比值从18增加到30.4和39.9。此外，水分在糖尿病兔晶状体内的扩散发生变化，细胞内沿皮质纤维长轴的流动性增加，如晶状体内的扩散系数由正常的0.48变为0.96× 10-5cm2s-1。这些结果表明，由于亚细胞干扰发生在任何明显的晶状体混浊之前，水的流动性发生了改变。此外，半乳性兔眼房水的水扩散率也从正常的1.77增加到2.67× 10-5 cm²s¹，表明自由水比例或热对流增加。结论：水自扩散阻力可能与晶状体纤维取向和细胞内蛋白顺序有关。因此，扩散成像可用于检查水的自扩散，以检测晶状体纤维的早期渗透改变。
Purpose: To examine water diffusion in the crystalline lens and sugar cataracts in the rabbits in vivo.Materials and Methods: Water self-diffusion in the lens cortices of alloxan-diabetic and galactosemic rabbits was examined with magnetic resonance imaging (MRI). The animals were positioned in a 4.7-tesla animal system in conjunction with a 1-inch surface coil for the eye. Diffusion-weighted MRI was conducted using a pulsed-gradient spin-echo sequence with a gradient strength of 0–6 Gs/cm in the primary and secondary coordinates. Other MRI parameters included TR (repetition time)/TE (echo time)= 2,000/10ms, a field of view of 4 cm, and a 256× 128 matrix.Results: There appeared an increase in water relaxation resulting in an increase of%(equatorial cortex depth)/(lens long axis) from 18 in the lenses of normal rabbits to 30.4 and 39.9 in the lenses of galactosemic and diabetic rabbits, respectively. In addition, water diffusion changed in the lens of the diabetic rabbit with an increasing intracellular fluidity along the long axis of the cortical fibers, for example, the diffusion coefficient changed from a normal of 0.48 to 0.96× 10-5cm2s-1 in the lens of the diabetic rabbit. These results showed altered water mobility due to subcellular disturbances occurring before any apparent lens opacities. Further, there also was an increase in the water diffusivity in the aqueous humor from a normal of 1.77 to 2.67× 10-5 cm² s¹ in the galactosemic rabbit eye suggesting an increase in either free water proportion or thermal convection.SConclusions: Resistance to water self-diffusion appeared to relate to lens fiber orienta-tion and intracellular protein order. Diffusion imaging therefore can be used to examine water self-diffusion to detect early osmotic alteration of lens fibers.