RESUMO
[Objective]To study the changes of the histomorphology and content of hydroxyproline that irradiated by 2.87 Mrad ?-rays in human tendon. [Methods]Forty fresh human tendons were freezed in-80℃ for six weeks,and randomly divided into two groups: the experimental group(group A) and control group(group B).Group A stored in dry ice was exposed to ?-rays until the absorbed dose reached 2.87 Mrad.The tendons was stained with HE and VG methods,and then observed by common light microscope and transmission electron microscope respectively.The content of hydroproline in tendon collagen hydrolysate was determined by the high performance liquid chromatography with precolumn derivation.[Results]①The results of histomorphology observation revealed that compared to the control group,the gaps between collagen fiber bands in irradiation group were enlarged,incompact,disordered and some of them fractured.The electron microscope observation showed that the transverse striation of the collagen fibers became unclear or disappeared.The membrane of tendon cell was dissolved,the cell nuclear was disintegrated and the organelles was reduced.②The content of hydroxyproline in the collagen hydrolysate of irradiation group was significantly higher than that in non-irradiation group under the same hydrolysis condition(P
RESUMO
This study aimed to estimate <I>in vivo</I> the compliance of tendon structure in human biceps brachii (BB) muscle for eight healthy male subjects. Elongation of the tendon of BB during isometric elbowflexion was directly measured by ultrasonography. Muscle force of BB (F<SUB>BB</SUB>) was calculated from the elbow flexion torque and moment arm of elbow-flexor. When the EBB increased to 80%MVC (maximum voluntary contraction), the tendinous tissue of BB was elongated 10.24±2.52 mm, horizontally. The relationship between tendon length and F<SUB>BB</SUB> was curvilinear and consisted of an initial region characterized by a large increase in tendon length with increasing F<SUB>BB</SUB> under 50%MVC, immediately followed by a linear region. The compliance of tendinous tissues, estimated from the slope of the linear region, was 0.010±0.005 mm N, and did not show a significant correlation with MVC and muscle volume of the elbow flexors, estimated from muscle thickness. The compliance value observed here was lower than those of the medial gastrocnemius muscle and the tibialis anterior muscle, reported previously using the same ultrasonic method as the present study. This may be related to the functional differences among limb muscles in various human movements.
RESUMO
The purpose of this study was to investigate the viscoelastic properties of tendon structures in humans. Elongation of the tendon and aponeurosis of medial gastrocnemius muscle (MG) was directly measured by ultrasonography, while subjects (N=12) performed ramp isometric plantar flexion up to the voluntary maximum, followed by a ramp relaxation. The relationship between estimated muscle force (Ff) and tendon elongation (dL) was fitted to a linear regression, the slope of which was defined as stiffness of the tendon structures. The hysteresis was calculated as the ratio of the area within the Ff-dL loop (elastic energy dissipated) to the area beneath the load portion of the curve (elastic energy input) . The resulting Ff-dL relationship was non-linear in form, as previously reported on animal and human tendons in vitro. The mean stiffness was 24.0±5.6 N/mm. However, there was a considerable inter-subject variability (15.8 to 36.8 N/mm) . The Young's modulus, i. e., the slope of the stress-strain curve, was 280 MPa, which tended to be lower than the previously reported values for human tendons. It was also found that the strain of the tendon structures was homogeneously distributed along its length. The mean hysteresis (energy dissipation) was 23.4±12.4%. However, again there was a considerable inter-subject variability (8.7 to 39.3%) . The present results indicated that the tendon structures of human MG was considerably compliant and its hysteresis was in accordance with previously reported values.