家兔腓肠肌肌构筑及肌纤维型的实验研究

A STUDY ON THE ARCHITECTURE AND FIBER TYPES OF THE GASTROCNEMIUS MUSCLE IN RABBIT

根据家兔（Ｏｒｙｃｔｏｌａｇｕｓｃｕｎｉｃｕｌｕｓｄｏｍｅｓｔｉｃａ）腓肠肌的肌构筑和神经供应特征，将该肌外侧头分为内侧、中间、外侧３个亚体，内侧头无肌亚体。用家兔８例１６侧腓肠肌，按上述３个亚体及内侧头分别取材，做冰冻横切片，肌动球朊ＡＴＰ酶染色，将肌纤维分为ＳＯ型、ＦＯＧ型和ＦＧ型。检测各亚体的肌纤维型构成比率，并以图象分析仪测量３型肌纤维的直径和横切面积。结果发现：ＳＯ型纤维在内侧头占１６．７％，在外侧头由内侧亚体的１１．３％向外侧亚体的２０．８％依次递增；ＦＯＧ型纤维由内侧亚体的２３．２％向外侧亚体的３０．９％递增。ＦＧ型纤维则从内侧亚体的６５．５％向外侧亚体的４８．３％逐渐递减。３型肌纤维成点缀式镶嵌型分布。各亚体中ＳＯ型纤维最细（５７．４—５８．２μｍ），ＦＯＧ型纤维稍粗（６０．１—６１．１μｍ），ＦＧ型纤维最粗（６３．６—６４．５μｍ）。

The gastrocnemius muscles of rabbits on both sides were studied Frozen transverse sections were stained with actomysin ATPase Muscle fibers were identified as type SO,type FOG and type FG The proportion of fiber types in each subvolume was calculated with microscopic photographs and the mean cross-sectional areas of three fiber types were measured with a image analysing system The following were found:(1)the proportion of SO fiber type in the medial gastrocnemius was 16 7%;(2)the proportion of SO fiber type increased progressively from 11 3% of the medial subvolume of the lateral gastrocnemius to 20 8% of the lateral subvolume;(3)the proportion of FOG fiber type increased progressively from 23 2% of medial subvolume to 30 9% of lateral subvolume;(4)the proportion of type FG fiber decreased successively from 65 5% of medial subvolume to 48 3% of lateral subvolume;(5)the three fiber types were in a mosaic pattern;(6)the diameter of type SO fiber in each subvolume was the smallest(57 4-58 2 μm),the diameter of type FOG fiber larger (60 1-61 1 μm),and the diameter of type FG fiber the largest(63 6-64 5 μm)