BIOMOMENTUM力學(xué)試驗機(jī)--游離鈣的變化改變椎間盤的機(jī)械性能

由于我們近發(fā)現(xiàn)人椎間盤（IVD）中游離鈣（Ca 2+）濃度升高會導(dǎo)致基質(zhì)降解（Grant等人ECM 2016），因此我們假設(shè)Ca 2+升高也會損害IVD力學(xué)。這項研究的目的是確定游離Ca 2+對IVD力學(xué)性能的影響。

從25個月大的牛尾中分離出IVD，并與1mM或5mM Ca 2+孵育4周。沒有鈣補(bǔ)充的IVD被認(rèn)為是對照。使用Mach-1機(jī)械測試儀（加拿大Biomomentum Inc.），對每個IVD進(jìn)行壓縮動態(tài)機(jī)械測試（DMA），以使用5％的應(yīng)變幅度在0.01Hz至5Hz的頻率范圍內(nèi)評估其體積楊氏模量（E *）。隨后，為了評估隔室的剛度，將IVD沿脊髓分為兩半，并使用自動球形壓痕技術(shù)（R = 3.2mm，15度量/ cm 2，振幅= 0.5 ）評估每半的中央部分毫米）。生成剛度圖。

與對照相比，在1mM或5mM Ca 2+中孵育4周后，E *明顯降低。與低Ca 2+濃度（1mM）的對照相比，IVD隔室的剛度幾乎保持不變，而在高
濃度（5mM）時達(dá)到顯著（p <0.0001 ）。纖維環(huán)（AF）的剛度從0.30±0.02MPa降低到0.06±0.01MPa。然而，對于髓核（NP）和終板（EP），組織剛度分別從0.030±0.001MPa增加到0.060±0.002MPa，從1.45±0.15MPa增加到2.5±0.07MPa
。

CHANGES IN FREE CALCIUM ALTER THE MECHANICAL PROPERTIES OF THE INTERVERTEBRAL DISC
Since we recently discovered that increased free calcium (Ca2+) concentration in the human intervertebral disc (IVD) leads to matrix degradation (Grant et al. ECM 2016), we hypothesized that elevations in Ca2+ also impair IVD mechanics. The aim of this study was to determine the effect of free Ca2+ on the mechanical properties of the IVD.

IVDs were isolated from 25-month-old bovine tails and incubated for 4 weeks with either 1mM or 5mM Ca2+. IVDs without calcium supplementation were considered as control. Using the Mach-1 mechanical tester (Biomomentum Inc, Canada), each IVD was subjected to compressive dynamic mechanical testing (DMA) to assess its bulk Young's modulus (E*) for frequencies ranging from 0.01Hz to 5Hz using 5% strain amplitude. Subsequently, to assess the compartmental stiffness, the IVDs were divided in two halves along the spinal cord, and the central section of each half was assessed using an automated spherical indentation technique (R=3.2mm, 15 measures/cm2, amplitude=0.5mm). Stiffness maps were generated.

After a 4-week incubation period in 1mM or 5mM Ca2+, E* decreased significantly compared to the control. Stiffness of IVD's compartments remained almost unchanged when compared to the control for low Ca2+ concentration (1mM), while it reached significance (p<0.0001) at the high
concentration (5mM). The stiffness decreased in annulus fibrosus (AF) from 0.30±0.02MPa to 0.06±0.01MPa. However, for both nucleus pulposus (NP) and endplates (EP), tissues stiffness increased from 0.030±0.001MPa to 0.060±0.002MPa and from 1.45±0.15MPa to 2.5±0.07MPa,
respectively.
High Ca2+ concentration alters IVD's bulk and compartmental mechanical properties. These results are consistent with our previous findings suggesting that increasing the calcium levels resulted in increases in the mineralisation of EP, and decrease the diffusion of nutrient into the disc. Consequently, assessing mechanical properties of each IVD's compartment may provide a better understanding of its bulk mechanical behavior and its integrity during degeneration.

Adapted from: I. Hadjab, M.P. Grant, L.M. Epure, M. Garon, E. Quenneville, J. Anthoniou, F. Mwale and M.D. Buschmann. Changes in Free Calcium Alter the Mechanical Properties of the Intervertebral Disc. International Conference on the Mechanics of Biomaterials and Tissues, Hawaii, USA, 12Dec2017, Podium O.48. 

biomomentum多軸機(jī)械測試儀Mach-1
 Mach-1多軸機(jī)械測試儀是模塊化集成壓縮，拉伸，剪切，摩擦，扭轉(zhuǎn)和3D壓痕映射、電位分布等測試設(shè)備
   biomomentum至1999年以來，專注用于測試生物材料，組織和關(guān)節(jié)軟骨機(jī)-電特性產(chǎn)品的設(shè)計、開發(fā)、制造和商業(yè)化的創(chuàng)新解決方案20余年。
    其mach-1多軸向多功能組織材料機(jī)械特性測試分析系統(tǒng)已經(jīng)成為組織材料機(jī)械-電位測試分析的黃金標(biāo)準(zhǔn)。
  1、多功能、多軸向，適用樣品范圍廣：
•1.1、從骨等硬組織材料到腦組織、眼角膜等極軟的組織材料
•1.2、從粗的椎間盤的樣品到極細(xì)的單纖維絲
2、力學(xué)類型測試分析功能齊全：
2.1、模塊化集成壓縮、張力、剪切、摩擦、扭轉(zhuǎn)、穿刺、摩擦和非平面壓痕、3D厚度、3D表面輪廓等各種力學(xué)類型支持,微觀結(jié)構(gòu)表征及動態(tài)力學(xué)分析研究
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•9、活性組織電位分布測試分析
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biomomentum多軸機(jī)械測試儀Mach-1材料力學(xué)性能簡介：
biomomentum多軸機(jī)械測試儀Mach-1材料力學(xué)性能是指材料在不同環(huán)境(溫度、介質(zhì)、濕度)下，承受各種外加載荷(拉伸、壓縮、彎曲、扭轉(zhuǎn)、沖擊、交變應(yīng)力等)時所表現(xiàn)出的力學(xué)特征。
可以放進(jìn)標(biāo)準(zhǔn)培養(yǎng)箱里進(jìn)行培養(yǎng)；
biomomentum多軸機(jī)械測試儀Mach-1測試意義及適用范圍：
材料力學(xué)性能可以應(yīng)用到生產(chǎn)的任何階段，從測試原材料質(zhì)量直到檢查制成品的耐用性。 測試可對廣泛多樣的生物樣品、材料和產(chǎn)品進(jìn)行，包括軟組織、軟骨組織、皮膚組織、凝膠組織、高分子材料、生物產(chǎn)品、醫(yī)學(xué)鑒定和水凝膠等。力學(xué)性能測試可幫助企業(yè)向客戶證明其產(chǎn)品的力學(xué)性能、穩(wěn)定性和安性，從而獲得基礎(chǔ)數(shù)據(jù)和競爭勢。
1、多功能、多軸向，適用樣品范圍廣：
1.1、從骨等硬組織材料到腦組織、眼角膜等極軟的組織材料
1.2、從粗的椎間盤的樣品到極細(xì)的單纖維絲
2、力學(xué)類型測試分析功能齊全：
2.1、模塊化集成壓縮、張力、剪切、摩擦、扭轉(zhuǎn)、穿刺、摩擦和非平面壓痕、3D厚度、3D表面輪廓等各種力學(xué)類型支持,微觀結(jié)構(gòu)表征及動態(tài)力學(xué)分析研究
2.2、多物理場耦合加載測試