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標題: | 超音波刺激對鼠尾肌腱纖維束黏彈性質之影響 Effects of Ultrasound Stimulation on Viscoelastic Properties of Rat Tail Tendon Fascicles |
作者: | Tzu-Hsuan Wu 吳姿萱 |
指導教授: | 王兆麟(Jaw-Lin Wang) |
關鍵字: | 大鼠尾巴肌腱,肌腱纖維束,肌腱生物力學,超音波刺激,超音波治療, Rat-tail tendon,Tendon fascicles,Tendon biomechanics,Ultrasound stimulation,Ultrasound therapy, |
出版年 : | 2018 |
學位: | 碩士 |
摘要: | 目的: 研究大鼠尾巴肌腱束在超音波刺激下的黏彈性質變化。
背景簡介: 肌腱的主要功能為連結肌肉組織與骨頭,並且幫助傳遞力量。鼠尾肌腱為一分級式結構,可粗分為纖維束、纖維以及微纖維。超音波刺激對生物組織的影響可分為兩種-熱效應以及非熱效應。熱效應之物理原理為因振動而產生熱能,已被廣泛應用於物理治療,而非熱效應之物理原理,一般認為包含了空穴效應、微流效應及頻率共振,臨床上常用來作為生物刺激、藥物釋放等之能量來源。除了熱效應以外,超音波對生物組織的黏彈性質影響尚未看到太多的研究,因此本研究擬針對超音波的非熱效應對肌腱組織之黏彈性質加以探討。 材料與方法: (一) 大鼠尾巴肌腱束製備: 本研究使用年齡三到十二月大之SD品系大鼠。大鼠在犧牲後即將鼠尾切下,小心地劃開大鼠尾巴表皮與破壞尾椎體後,將肌腱束由鼠尾末端抽出。每條肌腱束被切割為每四公分一段的試樣。每段試樣階透過倒立式光學顯微鏡拍攝並量測其截面積。(二) 超音波系統架置:超音波系統由輸入端至輸出端,依序由波型產生器、功率放大器、電功率計及其感測器、匹配電路及超音波探頭組成。超音波輸出強度由聲功率計及水聽計量測而得,在本實驗中其強度為 0.5 W/cm^2(ISPTA),頻率為3 MHz。(三) 力學測試:我們分別做了五種實驗,分別是靜態拉伸破壞測試,靜態鬆弛測試與靜態潛變測試,以及動態鬆弛測試與動態潛變測試。分別了解在這五種測試環境時,超音波刺激對鼠尾纖維束的強度以及黏彈性質的影響。(四)分析方法:我們使用標準線性固體模型之麥克斯威爾模型與凱文模型分別擬合動態靜態之鬆弛與潛變測試,得到各模型與測試時的楊式係數(E_1、E_2)、黏滯係數(η)和時間常數(τ)。 結果: (一) 靜態拉伸破壞測試:超音波刺激組的極限拉伸應力(49.9(27.4) MPa vs. 38.7(20.0) MPa, p=0.15)及線性模數(564(275) MPa vs. 460(153) MPa, p=0.15)較控制組大。(二) 靜態鬆弛測試:超音波刺激組與控制組在應力鬆弛百分比、模型分析係數部分皆無顯著差異。(三) 靜態潛變測試:超音波刺激組之應變增加量顯著小於控制組(3.0(0.8)% vs. 6.7(1.5)%, p<0.05),麥克斯威爾模型中係數E_1顯著大於控制組(99.2(13.6) vs. 51.3(9.7) MPa, p<0.05);凱文模型中係數E_1(137.1(11.6) MPa vs. 95.3(9.1) MPa, p<0.05)、E_2(561.8(149.6) MPA vs. 218.8(81.5) MPa, p<0.05)及η(212.1(68.4) GPa.s vs. 65(9.5) GPa.s, p<0.05)皆顯著大於控制組。(四) 動態鬆弛測試:動態鬆弛1,000循環後之破壞測試,控制組與超音波刺激組之結果並無顯著差異。針對前100循環變化較大之波峰資料點進行曲線分析,發現超音波刺激組之應力鬆弛百分比顯著低於控制組(25.9(7.2%) vs. 37.9(20.2)%, p<0.05)。麥克斯威爾模型中係數E_2顯著低於控制組(65.9(11.5) MPa vs. 112.7(19.6) MPa, p<0.05),時間常數則顯著高於控制組(30.1(2.6) sec vs. 23.7(1.6) sec, p<0.05);凱文模型中E_2及η具有大於,時間常數則具有小於控制組之趨勢。在結構模型中,超音波組之多醣基質彈性與黏性係數顯著低於控制組,時間常數顯著高於控制組。(五) 動態潛變測試:循環潛變1,000循環後之破壞測試顯示,控制組與超音波刺激組對強度並無顯著差異。針對1,000循環之波峰資料點進行曲線分析,發現超音波刺激組之潛變量顯著低於控制組(0.46(0.15)% vs. 0.35(0.20)%, p<0.05)。麥克斯威爾模型及凱文模型中,各項係數皆具大於控制組之趨勢,但未達到顯著程度。 結論: 超音波刺激造成大鼠尾巴肌腱束黏彈性質變化,黏彈性質的變化造成應力鬆弛量及潛變量的降低。由多種不同模型分析可發現,超音波刺激在動態環境中的影響較靜態顯著。超音波刺激對於靜態鬆弛中的肌腱之影響較小。而在潛變測試中,不論靜態或動態及現象模型,超音波刺激皆有使彈性係數及黏滯度增加的效果。可見超音波刺激對於運動中肌腱之影響較大,並且對於行潛變運動的肌腱影響最為顯著,而對於行靜態鬆弛的肌腱影響較小。 Objective: To investigate the effect of rat-tail tendon’s viscoelastic properties under ultrasound stimulation. Summary of background data: The biomechanical function of the tendon is to connect and deliver the force between muscle and bone. Rat-tail tendon is a hierarchical structure that can be classified as fascicle, fiber and fibril. The mechanical effect of ultrasound on soft tissue includes the thermal effect and non-thermal effect. The thermal effects is induced by the vibration within the living tissue, and this effect has been widely used in physiotherapy. The non-thermal effects of ultrasound includes cavitation, microstreaming and frequency resonance hypothesis, and can be used for tissue stimulation or drug release. In this study, we investigate the non-thermal effect of ultrasound on the viscoelastic properties of tendon fascicle. Methods: (1) Preparation of rat-tail tendon fascicles: Three to twelve months old SD rats were used in this study. After sacrificed, the rat tail was cut off, and the skin of the tail was peeled off. The tendon fascicles were carefully pulled out from the distal end of tail, and cut into 4 cm in length for testing. The cross sectional area of all samples were measured by inverted microscope. (2) Ultrasound system: The ultrasound system includes function generator, radio frequency amplifier, radio frequency power meter and its sensor, impedance matching circuit and ultrasound probe. The intensity of ultrasound field was measured by ultrasound acoustic power meter and hydrophone. In this study, ultrasound intensity was 0.5 W/cm^2 (ISPTA) and frequency was 3 MHz. (3) Mechanical testing protocol: The testing protocol includes 1. Ramp-to-failure test, 2. static relaxation test, 3. static creep test, 4. dynamic relaxation test, and 5. dynamic creep test. The effects of ultrasound on the stiffness and viscoelastic properties of tendon fascicles during these test were studied. (4) Method of analysis: standard linear solid models in Maxwell and Kelvin representation were used to find the tendon fascicles’ viscoelastic parameters, which includes Young’s modulus (E_1, E_2), viscosity (η) and time constant (τ) during static and dynamic relaxation and creep tests. Results: (1) Ramp-to-failure test: Experimental group has higher ultimate tensile strength (49.9(27.4) MPa vs. 38.7(20.0) MPa, p=0.15) and linear modulus (564(275) MPa vs. 460(153) MPa, p=0.15) than control group. (2) Static relaxation test: There is no significant difference between experimental group and control group in stress relaxation or viscoelastic properties. (3) Static creep test: Experimental group has significant lower amount of strain increase than control group (3.0(0.8) % vs. 6.7(1.5) %, p<0.05). In Maxwell representation model, experimental group has significant higher E_1 (99.2(13.6) vs. 51.3(9.7) MPa, p<0.05) than control group;In Kelvin representation model, experimental group has significant higher E_1 (137.1(11.6) MPa vs. 95.3(9.1) MPa, p<0.05), E_2 (561.8(149.6) MPA vs. 218.8(81.5) MPa, p<0.05) and η (212.1(68.4) GPa.s vs. 65(9.5) GPa.s, p<0.05) than control group. (4) Dynamic relaxation test: In ramp-to-failure test after cyclic loading, there is no significant difference between control group and experimental group in either failure stress or failure strain. The analysis of first 100 cycles showed the experimental group has significant lower amount of stress relaxation than control group (25.9(7.2) % vs. 37.9(20.2) %, p<0.05). In Maxwell representation model, experimental group has significant lower E_2 (65.9(11.5) MPa vs. 112.7(19.6) MPa, p<0.05) and significant higher time constant τ (30.1(2.6) sec vs. 23.7(1.6) sec, p<0.05) than control group;In Kelvin representation model, experimental group has higher tendency of E_2、η and time constant τ. In microstructural model, ultrasound stimulation group has significant lower elastic modulus and viscous modulus of proteoglycan matrix and significant higher time constant than control group. (5) Dynamic creep test: In the ramp-to-failure test after cyclic loading, there is no significant difference between control group and experimental group in either failure stress or failure strain. The analysis of 1,000 cycles showed experimental group has significant lower amount of strain increase than control group (0.46(0.15) % vs. 0.35(0.20) %, p<0.05). In Maxwell and Kelvin model, experimental group has higher tendency of all parameters than control group. Conclusion: Ultrasound stimulation changes the viscoelastic behavior of tendon fascicles. The change of viscoelastic properties reduced the relaxed stress and creep strain. The fitted models showed the effect of ultrasound is more prominent during dynamic tests than during the static tests. The effect of ultrasound on static relaxation test was minimal. During the creep test, elastic modulus and viscosity increase in static and dynamic loading condition increased, whereas the phenomenological model also showed similar effect. The results of this study may imply that the ultrasound affects the tendon’s properties during dynamic motion or exercise, especially for the dynamic creep motion, whereas the affect is minimal during static relaxation motion. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/72086 |
DOI: | 10.6342/NTU201803549 |
全文授權: | 有償授權 |
顯示於系所單位: | 醫學工程學研究所 |
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