长牡蛎闭壳肌肌纤维的组织学特性

分别利用石蜡切片苏木精-伊红染色法、冷冻切片烟酰胺腺嘌呤二核苷酸四唑氧化还原酶(NADH-TR)组化染色法、肌球蛋白ATP酶染色法对长牡蛎闭壳肌平滑肌和横纹肌进行了组织学特性研究,并比较平滑肌和横纹肌肌纤维组成的差异。石蜡切片结果显示,闭壳肌中平滑肌和横纹肌肌纤维形态结构不同,肌纤维直径、肌纤维密度和横截面积存在显著差异,其中平滑肌肌纤维直径为(5.97±0.631)μm,肌纤维密度为(25 485.65±3917.807)根/mm~2,肌纤维横截面积为(26.25±5.365)μm~2;横纹肌肌纤维直径为(7.41±0.847)μm,肌纤维密度为(16 908.25±3917.807)根/mm~2,横截面积为(40.45±10.083)μm~2。NADH-TR染色结果显示,平滑肌中富含NADH,肌纤维染色较深,呈现深蓝紫色,主要是I型肌纤维,为氧化代谢的慢速收缩型肌纤维;横纹肌染色较浅或者基本不着色,主要是II型肌纤维,为糖酵解代谢的快速收缩肌纤维。ATPase酶染色结果显示,横纹肌ATPase活性强,染色较深,呈现黑色,主要是II型肌纤维;平滑肌中ATPase活性弱,着色浅或基本不着色,主要是I型肌纤维。ATPase酶染色结果与NADH-TR染色结果一致。研究阐明了长牡蛎闭壳肌中平滑肌和横纹肌肌纤维的组织学特性及收缩、代谢特性差异,为深入研究长牡蛎肌纤维生物学特性提供了重要的基础资料,为提高我国贝类肉质品质提供理论依据。

Histological studies on the muscle fibers of Crassostrea gigas adductor

Paraffin embedded tissue section and hematoxylin-eosin staining were used to investigate the morphological characteristics of smooth and striated adductor muscles in Crassostrea gigas.Muscle fibers were stained histochemically for NADH-diaphorase and adenosine triphosphatase activity (ATPase) to identify fiber types in smooth and striated muscles.The morphological characteristics of myofibers within smooth and striated muscles were compared by quantifying muscle diameter and cross-sectional area.Muscle fiber diameter in smooth muscle (5.97 μm) was significantly smaller than that in striated muscle (7.41 μm) (P＜0.05).Muscle fiber density of smooth muscle (25 485.65±3917.807 n/mm2) was significantly higher than that in striated muscle (16 908.25±3917.807 n/mm2).The cross-sectional area of myofibers in striated muscle (40.45 μm2) was significantly greater than that in smooth muscle (26.25 μm2,P＜0.05).The result of NADH-TR histochemistry showed that the myofibers in smooth muscle were slow oxidative fibers (type I),as indicated by positive blue reat unstained by NADH-TR.ATPase histochemistry revealed that fibers in striated muscle were intensively stained and the fibers was type II with a high ATPase activity.The fibers in smooth muscle were lightly stained or unstained,suggesting the fibers were type I.The results of ATPase/NADH-TR staining were consistent.In this study,we firstly illustrated the morphological characteristics of myofibers in smooth and striated adductor muscles of C.gigas,and compared the differences in contraction and metabolic profiles between smooth and striated muscles.This research not only provides important information for in-depth studies on biological characteristics of muscle fibers in C.gigas,but also provides theoretical basis for improving the meat quality of molluscs.