射頻輻射對蝕骨細胞胞飲磁性奈米粒子之熱效應探討

The Studies of the Thermal Effects Mediated by Radiofrequency on the Osteoclasts Endocytosed Magnetite Nanoparticles

巫珮如(Pei-Ru Wu)

指導教授 ： 婁世亮

中原大學/工學院/生物醫學工程學系/碩士(2008年)

https://doi.org/10.6840/cycu200900360

摘要

摘要
骨質疏鬆症引發的骨折危害人體甚巨。骨質疏鬆症導因於骨骼之蝕骨細胞對骨骼再吸收作用大於造骨細胞形成骨基質作用。臨床上的治療大都使用藥物抑制蝕骨細胞數量和活性。然而，藥物的療效與副作用，優劣互見。本研究則是以熱裂解蝕骨細胞的方式取代藥物控制。在構思上，是以射頻 (radio frequency, RF) 輻射蝕骨細胞所胞飲之磁性奈米粒子，產生熱效應，進而達到裂解蝕骨細胞的目的。
研究中所使用之奈米粒子含有磁性奈米粒子 ( Fe3O4 ) 和重量比1：1與1：2多醣體磁性奈米粒子複合物，都是以共沈澱法自製合成。蝕骨細胞培養模式使用RAW 264.7老鼠單核球細胞做為分化成多核蝕骨細胞前驅細胞，將老鼠單核球前驅細胞加入RANKL誘導形成多核類蝕骨細胞。繼以射頻輻射磁性奈米粒子和多醣體磁性奈米粒子複合物及胞飲有奈米粒子之類蝕骨細胞，進行溫升探討，射頻系統使用頻率為42 kHZ，磁性奈米粒子和多醣體磁性奈米粒子複合物重量分別為1、3和5 mg，使用射頻系統曝曬10分鐘。射頻輻射類蝕骨細胞胞飲磁性奈米粒子之溫升效應，細胞存活率使用MTT測試。
結果顯示，本研究自製之奈米粒子均不具細胞毒性。類蝕骨細胞培養表現出同蝕骨細胞特性及於碳酸鈣磷酸鹽薄膜再吸收功能性，將所有自製之奈米粒子分別與類蝕骨細胞共培養，確認類蝕骨細胞對磁性奈米粒子的胞飲現象。1 mg磁性奈米粒子經射頻輻射，在1分鐘內溫度上升50 oC，相同重量1：1與1：2多醣體磁性奈米粒子複合物經射頻輻射1分鐘內溫升效應不如磁性奈米粒子，其溫升分別為17.83 oC與17.23 oC。射頻輻射奈米粒子溫升效應隨奈米粒子濃度增加其溫度成比例上升，另一方面，本研究使用多醣體披覆磁性奈米粒子已達到飽和狀態，多醣體披覆濃度提高，射頻輻射奈米粒子溫升效應下降。此外，當磁性奈米粒子分散於細胞培養液中，射頻溫升效果降低，但該溫升已足以促使類蝕骨細胞存活率降低。
據此，吾人以為，運用射頻輻射磁性奈米粒子之溫升作用具有裂解蝕骨細胞的效果，有助於控制骨質疏鬆症惡化的可行性。

關鍵字

蝕骨細胞 ； 熱效應 ； 磁性奈米粒子 ； 射頻輻射

並列摘要

Abstract
Osteoporosis associated bone fracture is a medical condition that severely threatens lives. The cause of osteoporosis is the imbalance activity of bone resorption process and bone formation process. In bone, osteoclasts (OC) are responsible for the bone resorption and osteoblasts (OB) are involved in the bone matrix synthesis. Osteoporosis symptom occurs when the OC resorption is more active than the OB formation. The current approach to control the number and the activity of OC is by medicine. However, the treatment effects and the adverse effects of today’s medicines are mixed.
Rather than using medicines alone, an approach of applying thermolysis technique to limit the quantity of osteoclast is proposed in this study. The technique is performed in a way that magnetite (Fe3O4) nanoparticles are engulfed by osteoclasts (i.e. endocytosis) and then the osteoclasts die from thermal effect of magnetite nanoparticles resulted from radio frequency (RF) exposures. In this study, magnetite, magnetite-dextran 1:1 (w%) and 1:2 (w%) nanoparticles were prepared by a chemical co-precipitation method. These nanoparticles were through physical and chemical analyses and cytotoxic evaluations. RAW 264.7 mouse monocytes were used as a model system for the differentiation of multinucleated osteoclasts from mononucleated precursors. These monocytes were induced with RANKL to form multinucleated giant osteoclast-like cells (OCLs). The thermal effects of the synthesized nanoparticles in weights of 1, 3 and 5 mg for a 10-minute exposure were studied. The RF system used in this work was set to produce 42-KHz electromagnetic wave. The nanoparticle-endocytosed OCLs were radiated and then evaluated by MTT tests.
The cytotoxicity test results indicate that both the magnetite and magnetite-dextran nanoparticles prepared in this study are non-cytotoxic. The OCLs express a number of osteoclast-specific markers and were able to form resorption pits on calcium phosphate films. The endocytosis of the magnetite and magnetite-dextran nanoparticles was confirmed. For the magnetite nanoparticles of 1 mg receiving the RF exposures, temperature increased 50 oC in about 60 seconds. The increases were reduced to 17.83 oC and 17.23 oC for the same quantity of the magnetite-dextran nanoparticles 1:1 and 1:2, respectively. The induced temperature increase is proportional to the nanoparticle quantity. On the other hand, the dextran content in the magnetite-dextran nanoparticles increases, the thermal effect decreases. In addition, the medium used for culturing the OCLs is a factor reducing the thermal effect. Fortunately, the temperature increase induced by the RF is sufficient to kill the OCLs.
In conclusion, the thermolysis of the OCLs is achievable by inducing the thermal effect of magnetite nanoparticles with the RF radiations. This implies that there is a potential of using the thermolysis technique to alleviate osteoporosis.

並列關鍵字

Osteoclast ； Thermal effect ； Radio frequency ； Magnetite nanoparticle

參考文獻

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