大鼠老化进程中晶状体蛋白水溶性向水不溶性的转变

Change of crystallins from water soluble into insoluble with ageing of rat

目的:研究大鼠老化进程中晶状体蛋白由水溶性向水不溶性的转变特性,探讨对老年性白内障形成的可能作用。方法:采用双向电泳法,分析SD大鼠在老化进程中不同阶段(出生后1,8d;2,8wk;8mo;1.5a)晶状体蛋白α,β,γ由水溶性向水不溶性的时相性转变特性。结果:各年龄组大鼠晶状体蛋白水溶性及水不溶性成分的双向电泳图谱模式有较大相似性。结构蛋白αA2,αB2,βB2随老化进程,其水溶性成分均呈升高趋势;水不溶性成分中αA2,βB2含量亦随年龄增长而升高,αB2在大鼠出生8mo后呈明显升高。晶状体蛋白自出生后8wk起,即发生明显的翻译后修饰(蛋白斑点增加),尤其伴侣蛋白αA2,αB2,同时也是结构蛋白)随老化其修饰成分增加十分明显,在水不溶性成分图谱中表现更为突出。出生后8wk前,βB2晶状体蛋白无论在水溶性或水不溶性成分中含量均极少;发育渐趋成熟该蛋白含量快速增加;出生8mo后成为晶状体蛋白中的主要成分,1.5a起成为含量最高的成分。结论:在大鼠老化进程中,不同晶状体蛋白其水溶性及水不溶性成分的变化趋势呈现不同特性。同种晶状体蛋白在不同年龄段存在量和/或质的变化。大鼠成长过程中晶状体蛋白变性显见于出生后8wk,其程度随老化而加重。

AIM： To study the property of phasic changing of crystallins of SD rat from water soluble into water insoluble with aging and its role in the development of senile cataract. METHODS： Phasic changing of the three major crystallins （α, β,γ groups） were detected by two dimensional electrophoresis with aging （day 1,8;week 2, 8;month 8 and year 1.5 after birth） and also analyzed their property during the turning process. RESULTS： The patterns of their composition of both water soluble and insOluble crystallins were similar in different aging groups as detected by two dimensional electrophorasis. The relative quantity of the three major crystallins （αA2,αB2,βB2） increased as the ageing process in the water soluble fraction, but in water insoluble fraction, onlyo A2,βB2 crystallins increased as the aging process and the quantity ofo B2 increased significantly until 8 months after birth. Post-translation modification was observed in the major crystallins since 8 weeks after birth （increased crystallin spots） and the modification extent of chaperone crystallins （αA2,α B2,also are major structure proteins of lens）were apparent during the aging process, especially in the water insoluble fraction. The quantity of βB2 crystllin was relatively very low before the rat was 8 week old both in water soluble or water insoluble fraction, but increased quickly and became into the major constituent of lens proteins after 8 months old and even became into the highest one after 1.5 year old. CONCLUSION： There is different changing property and trending of the crystallins from water soluble into water insoluble fraction during the aging process for different crystallins. The quantity and （or） quality of a single crystallin change in different way with the different aging stage. Crystallins can be modified by many factors during ageing as the post translation modification, which become apparent even in the early stage （8 weeks after birth） and aggravate following the ageing process.