Kawata Tetsuhiro, Matsuo Toshihiko, Uchida Tetsuya
Department of Ophthalmology, Okayama University Medical School and Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, 700-8558 Japan.
Division of Polymer Materials Science, Faculty of Engineering and Okayama University Graduate School of Natural Science and Technology, Okayama, Japan.
Springerplus. 2014 Jun 25;3:317. doi: 10.1186/2193-1801-3-317. eCollection 2014.
Glass transition temperature is a main indicator for amorphous polymers and biological macromolecules as materials, and would be a key for understanding the role of trehalose in protecting proteins and cells against desiccation. In this study, we measured the glass transition temperature by differential scanning calorimetry of dried lens tissues as a model of a whole biological tissue to know the effect of pretreatment by trehalose and other sugars.
Isolated porcine lenses were incubated with saline, 100 or 1000 mM concentration of trehalose, maltose, or cyclic tetrasaccharide dissolved in saline at room temperature for 150 minutes. The solutions were removed and all samples were dried at room temperature in a desiccator until no weight change. The dried tissues were ground into powder and placed in a measuring pan for differential scanning calorimetry.
The glass transition temperature of the dried lens tissues, as a mean and standard deviation, was 63.0 ± 6.4°C (n = 3) with saline pretreatment; 53.0 ± 0.8°C and 56.3 ± 2.7°C (n = 3), respectively, with 100 and 1000 mM trehalose pretreatment; 56.0 ± 1.6°C and 55.8 ± 1.1°C (n = 3), respectively, with 100 and 1000 mM maltose pretreatment; 60.0 ± 8.8°C and 59.2 ± 6.3°C (n = 3), respectively, with 100 and 1000 mM cyclic tetrasaccharide pretreatment. The glass transition temperature appeared lower, although not significantly, with trehalose and maltose pretreatments than with saline and cyclic tetrasaccharide pretreatments (P > 0.05, Kruskal-Wallis test). The glass transition temperature of the dried lens tissues with trehalose pretreatment appeared more noticeable on the thermogram, compared with other pretreatments.
The glass transition temperature was measured for the first time in the dried lens tissues as an example of a whole biological tissue and might provide a basis for tissue preservation in the dried condition.
玻璃化转变温度是无定形聚合物和生物大分子作为材料的主要指标，对于理解海藻糖在保护蛋白质和细胞免受干燥影响方面的作用至关重要。在本研究中，我们通过差示扫描量热法测量干燥晶状体组织的玻璃化转变温度，以整个生物组织为模型，了解海藻糖和其他糖类预处理的效果。
将分离的猪晶状体在室温下用盐水、溶解于盐水中浓度为100或1000 mM的海藻糖、麦芽糖或环四糖孵育150分钟。去除溶液，所有样品在室温下于干燥器中干燥至重量不再变化。将干燥的组织研磨成粉末，放入测量盘中进行差示扫描量热法测定。
经盐水预处理的干燥晶状体组织的玻璃化转变温度，以平均值和标准差表示，为63.0±6.4°C（n = 3）；经100和1000 mM海藻糖预处理的分别为53.0±0.8°C和56.3±2.7°C（n = 3）；经100和1000 mM麦芽糖预处理的分别为56.0±1.6°C和55.8±1.1°C（n = 3）；经100和1000 mM环四糖预处理的分别为60.0±8.8°C和59.2±6.3°C（n = 3）。与盐水和环四糖预处理相比，海藻糖和麦芽糖预处理的玻璃化转变温度虽无显著差异但呈现较低趋势（P>0.05，Kruskal-Wallis检验）。与其他预处理相比，经海藻糖预处理的干燥晶状体组织的玻璃化转变温度在热谱图上更为明显。
首次以干燥晶状体组织为例，作为整个生物组织测量其玻璃化转变温度，这可能为干燥条件下的组织保存提供依据。
