新西兰白兔生后骨骼肌发育的超微结构及组织化学研究

Studies on the Light and Electron Microscopic Structure and the Histo一chemistry of the Skeletal Fibers of New Zealand Rabbits at Postbirth Stage

通过组织学、组织化学和超薄切片的方法对生后不同日龄新西兰白兔的骨骼肌发育特，点进行了系统研究。研究表明，初生兔在组织学结构和ＳＤＨ酶的分布等方面尚未发育完善，需在生后一周左右才发育成熟，骨骼肌纤维才可区分为：红肌纤维、白肌纤维和中间型肌纤维三种类型。三种肌纤维类型所占比例随着兔的生长发育而发生变化。骨骼肌的迅速生长期主要在初生至６周龄。６周龄时，肌纤维的直径、肌原纤维直径及每根肌原纤维所含的微肌丝数分别比初生时增加了７０％、１８８％和１７９％，但肌桨部分的比例（即不含肌纤维的胞桨部分）下降５３．４６％，其中肌原纤维中的微肌丝数量的迅速增加是导致肌纤维直径迅速增长及胞桨比例下降的主要原因。因此，在初生１６周龄期间提供足够的蛋白质营养，无论对肌纤维的酶分化，还是对其生长发育都十分重要。新西兰白兔的骨骼肌纤维由肌节为单位组成，肌节的基本结构在胚胎期就已决定，不随兔日龄的增长而变化，而与科属特性有关。随着兔的生长发育，骨骼肌纤维的糖原、线粒体、脂滴和肌桨网终池等呈现出规律性变化。１２周龄兔的肌纤维直径较细，细胞中含有中等量的线粒体、糖原及肌桨网终池。

s The structure of the muscle fibers of New ZeaLand at 0一,2 ,3一,4一,6一,8一,10 ,and 12一weekages was studied at light and dectron levels .It was shown that:The diameter of the muscle fibers increased with the increment of the myofibril diameter andthd number of the muscle filaments. The maximum growth rate of the muscle fiber diameter oc-curred between 0 week and 6 weeks. But the fiber structure did not fully develope and was not di-vided into white,intermediary and red fibers until一week age. The percentages of the muscle types changed with the age of the rabbit and the location ofthe skeletal muscle in the body. The number of fat bodies,glycogen granules and mitochondria also changed with the age ofthe rabbits. However,the ultrastructure of the sarcomere changed was not changed significantlyafter birth.