Meibomian Lipid Films and the Impact of Temperature
Meibomian Lipid Films and the Impact of Temperature
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DOI：
10.1167/iovs.10-5419
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发表时间：
2010-11-01
影响因子：
4.4
通讯作者：
Wojtowicz, Jadwiga C.
中科院分区：
文献类型：
--
作者：
Butovich, Igor A.;Arciniega, Juan C.;Wojtowicz, Jadwiga C.
目的。有证据表明，在寒冷条件下，人类眼睑和眼表的温度远低于正常生理水平。这可能对人泪膜和泪膜脂质层的稳定性和功能产生不利影响。该项目的目标是定量研究温度对后者可能的影响。方法。使用软挤压技术收集睑脂样品并在朗缪尔槽中进行研究。对获得的表面压力和面积等温线进行分析，以确定薄睑板脂膜（MLF）的生物物理参数：剥离面积、塌陷压力、二维弹性和滞后及其对温度的依赖性。结果。人们发现 MLF 对温度变化非常敏感。当温度低于生理水平时，MLF 会变得僵硬并大幅收缩。收缩使得空气-水界面的大部分未被脂质分子覆盖。该效应被证明是可逆的。重新加热时，脂质融化并重新扩散，恢复原来的薄膜。在空气-水界面处，散装干睑脂的三维熔化与 MLF 的二维熔化之间存在根本差异。块状睑脂在较窄的温度范围内熔化并表现出较高的熔化协同性。结论。温度对 MLF 影响很大。低温导致薄膜变硬，失去在空气-水界面形成连续层的能力。这些效应具有协同作用，表现在相对较窄的浓度和温度范围内。 （投资眼科可见科学。2010；51：5508-5518）DOI：10.1167/iovs.10-5419
PURPOSE. There is evidence that, in cold conditions, the temperature of human eyelids and of the ocular surface drops well below normal physiological levels. This may have a detrimental impact on the stability and functionality of the human tear film and the tear film lipid layer. The goal of this project was to quantitatively examine the possible impact of temperature on the latter.METHODS. Meibum samples were collected by using a soft-squeezing technique and were studied in a Langmuir trough. The obtained surface pressure and area isotherms were analyzed to determine the biophysical parameters of thin meibomian lipid film (MLF): the lift-off area, collapse pressure, two-dimensional elasticity, and hysteresis and their dependence on temperature.RESULTS. MLF was found to be highly susceptible to changes in temperature. At temperatures below the physiological level, the MLF became stiff and shrank considerably. The shrinkage left a large portion of the air-water interface uncovered with lipid molecules. The effect was shown to be reversible. On reheating, the lipids melted and respread to restore the original film. There was a fundamental difference observed between three-dimensional melting of dry meibum in bulk and the two-dimensional melting in MLF at the air-water interface. Bulk meibum melted in a narrower temperature range and showed a much higher cooperativity of melting.CONCLUSIONS. Temperature critically influences MLF. Low temperature leads to stiffening of the film, which loses its ability to form continuous layers at the air-water interface. These effects were shown be of a cooperative nature, manifesting in relatively narrow concentration and temperature ranges. (Invest Ophthalmol Vis Sci. 2010;51:5508-5518) DOI: 10.1167/iovs.10-5419