低能量超音波及功能性電刺激對於骨骼系統之影響

Effects of Low-Intensity Pulsed Ultrasound and Functional Electrical Stimulation on Skeletal System

賴建宏(Chien-Hung Lai)

指導教授 ： 張恆雄

中原大學/工學院/生物醫學工程研究所/博士(2010年)

https://doi.org/10.6840/cycu201000178

摘要

中文摘要
骨質疏鬆(Osteoporosis)是殘障病人常見併發症，這些骨質疏鬆的病人，常因日常生活中輕微受傷就造成骨折。骨折後之癒合也是極度複雜的過程，癒合不良在臨床上往往造成高致病率。因此，如何預防骨質疏鬆與避免骨折，以及骨折後如何防止癒合不良，是很重要的課題。細胞接受機械拉力後，會造成骨骼系統之生化反應而刺激骨生成，超音波(non-invasive low-energy ultrasound)及功能性電刺激踩車系統 (functional electrical stimulation cycling exercises) 在骨骼系統會有類似機械拉力的作用，因此本博士論文分成二部份：包括超音波對於人類間葉幹細胞分化成軟骨與骨細胞的影響之實驗及功能性電刺激踩車在骨質流失之臨床研究。
第一部份之研究目的為：探討超音波及細胞激素對於人類間葉幹細胞(human mesenchymal stem cells ;hMSCs) 軟骨分化(chondrogenic differentiation)與骨分化(osteogenic differentiation)之影響。此研究分別用合成皮質類固醇 / 轉化生長因子(dexamethasone/transforming growth factor :TD)或骨頭生成蛋白質(bone morphogenetic protein-2 ;BMP-2)下，在有或無給予超音波處置下，人類間葉幹細胞軟骨化或骨化之變化。我們分析細胞外型變化，並運用及時聚合鏈反應(real-time polymerase chain reaction )分析軟骨化(chondrogenic)及骨化(osteogenic)之基因表現 (messenger RNA expression)。TD處置之人類間葉幹細胞顯示明顯軟骨化細胞形狀及增加軟骨化基因表現，給予超音波和TD處置預期有加乘作用。就骨化的基因表現而言，超音波和骨生成蛋白質分別都會刺激骨化之基因表現，但二者一起作用卻沒有顯示明顯加乘效果。因此超音波可能對於間葉細胞軟骨分化及骨分化有不同影響。這個結果可以提供在使用超音波促進軟骨及骨頭修復上之臨床參考。
第二部分之研究為與骨密度(bone mineral density)相關之臨床實驗，這個研究主要目的為早期給予脊髓損傷者(spinal cord injury)功能性電刺激踩車訓練，是否可以預防或減輕骨質疏鬆？另外也分析若停止踩車訓練後，此一預防或減輕骨質疏鬆的效果是否依然存在？本研究共有24位受傷後26至52天之脊髓損傷患者參加，其中12位加入功能性電刺激踩車組，另外12位為控制組。功能性電刺激踩車組患者接受3個月踩車訓練，然後停止訓練3個月，患者之股骨頸(femoral neck )及遠端股骨(distal femur)分別於訓練前後三個月後，及停止訓練三個月後，運用雙光光子測量法(dual energy X-ray absorptiometry)來測量骨密度，結果顯示：在功能性電刺激踩車訓練三個月期間，訓練組之遠端股骨骨密度下降率明顯少於控制組，但是停止訓練三個月期間，二組間遠端股骨骨密度下降率並無差異。因此，功能性電刺激踩車訓練可以部份減輕遠端股骨之骨密度流失，但是此訓練無法完全阻止骨密度流失。另外，在停止訓練後，減輕骨密度流失之效果無法持續。
由上述二部份研究讓我們了解到，超音波和功能性電刺激踩車這二種會產生機械拉力的物理因子，會對骨骼系統產生正向影響。超音波會改善間葉幹細胞往軟骨及骨細胞分化，而功能性電刺激踩車訓練可以減輕遠端股骨骨質的流失。

關鍵字

功能性電刺激踩車 ； 軟骨分化 ； 骨分化 ； 超音波 ； 人類間葉幹細胞 ； 脊髓損傷者 ； 骨密度

並列摘要

Abstract
Osteoporosis is a well-recognized complication among disabled individuals. Secondary to the characteristic bone loss of osteoporosis, fractures caused by minimal trauma often occur among these individuals. Therefore, prevention of osteoporosis and subsequent reduction in fractures due to bone loss in disabled subjects is an important issue. Additionally, healing of fractures is an extremely complex process; delayed union or non-union are frequently observed in clinical practice and present potential morbidities. The mechanical strain received by cells may result in biochemical events that, in the skeleton, have been shown to promote bone formation. Non-invasive low intensity pulsed ultrasound (LIPUS) and functional electrical stimulation cycling exercises (FESCE) can mimic the effects of mechanical loading on bone. This dissertation addresses these treatment modalities and consists of two parts: the investigation of LIPUS in in vitro models and the investigation of FESCE in clinical circumstances involving bone regeneration.
In the first part of this study, the effects of LIPUS on the differentiation of human mesenchymal stem cells (hMSCs) were investigated. The hMSCs were subjected to LIPUS either with or without dexamethasone/transforming growth factor-β1 (TD) or bone morphogenetic protein-2 (BMP-2), and the effects of these treatments were assessed in two groups, a LIPUS-only group and a LIPUS-with-TD treatment group. The TD-treated hMSCs exhibited characteristic chondrogenic morphology and increased mRNA expression of chondrogenic markers, and LIPUS enhanced the chondrogenic differentiation of hMSCs treated with TD. No alterations were seen in the expression of Runx2, an osteogenic transcription factor, in either the LIPUS-only group or the LIPUS-with-TD treatment group; however, a significant increase was detected in the LIPUS-only group. The osteogenic appearance was seen three days after LIPUS and/or BMP-2 treatment. Increases in the mRNA expression levels of osteogenic markers, Runx2 and ALP were also detected. No additive or altered effects were noted with combined LIPUS and BMP-2 treatment. LIPUS alone can increase osteogenic differentiation of hMSCs and LIPUS enhances TD-mediated chondrogenic differentiation of hMSCs. Clinically, LIPUS may differentially influence bone versus cartilage repair.
The second part of this study was designed to determine whether loss of bone mineral density (BMD) after spinal cord injury (SCI) can be attenuated by early intervention with FESCE and to ascertain whether the effect persists after FESCE is discontinued.
Twenty-four patients with SCI, 26-52 days after injury, were divided into a FESCE group and a control group. In the treatment group, FESCE was applied in the initial three months and then suspended in the subsequent three months. BMDs of the femoral neck and distal femur (DF) were obtained by dual energy X-ray absorptiometry (DXA) before training, immediately after the initial three months of training, and at the end of the subsequent three months. During the initial three months, the reduction rate for BMD in the DF of the FESCE group was significantly less than that of the control group. However, no significant differences were noted in the subsequent three months when treatment was suspended. In summary, FESCE in the early stages of SCI can partly attenuate BMD loss in the DF. However, BMD loss in the DF cannot be ameliorated completely by FESCE. In addition, the effect on the attenuation of bone loss in the DF faded once FESCE was discontinued.
These findings suggest that LIPUS and FESCE mimicking mechanical strain may have a positive skeletal impact. LIPUS enhances chondrogenic differentiation of hMSCs that have received TD induction and promotes osteogenic differentiation of hMSC. FESCE applied in the early stages of SCI can partly attenuate BMD loss in the DF.

並列關鍵字

Spinal cord injury (SCI) ； Bone mineral density (BMD) ； Osteogenic differentiation ； Chondrogenic differentiation ； Human mesenchymal stem cells (hMSCs) ； Low-intensity pulsed ultrasound (LIPUS) ； Functional electrical stimulation cycling exercise (FESCE)

參考文獻

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