Simůnek Z, Muir H
Biochem J. 1972 Feb;126(3):515-23. doi: 10.1042/bj1260515.
Analysis of the knee-joint cartilage of pigs at five ages (namely foetuses from the second half of pregnancy and animals 10 weeks, 25 weeks, 3 years and 5 years old) showed that the composition approached that of adult cartilage by 25 weeks of age, the most marked differences being between foetal and 10 week-old cartilage. Protein-polysaccharides were extracted sequentially, first by brief low-speed homogenization with iso-osmotic sodium acetate, then by two extractions with 2m-CaCl(2) for 24h with gentle agitation interspersed with brief low-speed homogenization and agitation for another 24h. About half of the protein-polysaccharides were removed from foetal cartilage by the first extraction and the remainder by the second. The proportion in the first extract declined sharply with the age of the animal, but that in the first CaCl(2) extract was similar at all ages other than 10 weeks. The amount left in the residue increased approximately with the collagen content from about one-fifth at 10 weeks of age to one-third in adult and old cartilage. The proportion of medium-sized protein-polysaccharides in the extracts changed little with age after birth, but the glucosamine content increased about fivefold and the protein content almost doubled between 10 weeks and 5 years of age. Other analytical values changed little. These results cannot be explained solely by changes in the proportion of ;link-glycoprotein' in the protein-polysaccharides. Since major changes in most parameters had taken place by 25 weeks of age, the first weeks after birth may be a critical period for cartilage development in the pig.
对五个年龄段猪的膝关节软骨进行分析（即妊娠后期的胎儿以及10周龄、25周龄、3岁和5岁的动物），结果显示到25周龄时软骨成分已接近成年软骨，胎儿软骨与10周龄软骨之间差异最为显著。依次提取蛋白多糖，首先用等渗醋酸钠进行短暂低速匀浆，然后用2m氯化钙分两次提取，每次提取24小时，期间轻轻搅拌，穿插短暂低速匀浆并再搅拌24小时。胎儿软骨中的蛋白多糖约一半在第一次提取时被去除，其余的在第二次提取时被去除。第一次提取物中的比例随动物年龄急剧下降，但除10周龄外，第一次氯化钙提取物中的比例在所有年龄段都相似。残留物中剩余的量随胶原蛋白含量大致增加，从10周龄时的约五分之一增加到成年和老龄软骨中的三分之一。出生后提取物中中等大小蛋白多糖的比例随年龄变化不大，但氨基葡萄糖含量增加约五倍，蛋白质含量在10周龄至5岁之间几乎翻倍。其他分析值变化不大。这些结果不能仅用蛋白多糖中“连接糖蛋白”比例的变化来解释。由于大多数参数在25周龄时已发生重大变化，出生后的头几周可能是猪软骨发育的关键时期。
