骨内微管中流动电位的实验研究

An Experimental Study on the Behavior of Streaming Potentials in Bone Microchannels

力学载荷是骨量和结构的重要调节因素,骨重建与骨的形成和代谢密切相关。研究认为骨的力电性质是骨重建与力学载荷之间的纽带,而骨的力电性质中一个重要的研究方向就是流动电位。此研究的目的在于通过实验确定缓冲液流经哈佛氏管与骨小管时所产生的流动电位的差别。选取8个样本,使用自行设计的测试系统,测量5种不同加载速率下骨试样的流动电位。将骨试样的侧表面由硅橡胶密封,模拟缓冲液主要通过哈佛氏管流动的情形;而未密封的情况,则模拟缓冲液同时流经哈佛氏管以及试样表面上被剖开的骨单元中骨小管的情形。结果显示,对应于加载速率26、36、60、180、360 kPa/s,侧表面密封时,流动电位稳定值分别为(0.29±0.09)、(0.24±0.06)、(0.21±0.05)、(0.19±0.05)、(0.16±0.04)mV;侧表面未密封时,流动电位稳定值分别为(0.69±0.08)、(0.61±0.09)、(0.57±0.07)、(0.51±0.05)、(0.46±0.05)mV。未密封时流动电位明显高于密封时的流动电位(P值均小于0.05),而且两者的电位差反映了缓冲液流经骨小管时所产生的流动电位要明显高于流经哈佛氏管的时候。基于骨的微观结构,并考虑到骨细胞主要分布在骨小管附近,实验结果为研究流动电位与骨的重建问题提供了依据。

Mechanical loading is an important regulatory factor for bone mass and structure. Bone remodeling and formation are closely associated to metabolism. It is considered that eleetromechanical property of bone is a link between bone remodeling and mechanical loading, therefore, the streaming potential is one important direction in the electromechanical property of bone. The objective of this study is to confirm the difference of the produced streaming potential from buffer solution flowing through Haversian canal and bone canalicules by experiments. The streaming potential of eight bone specimens under five different loading rates was measured using self-designed testing system. The lateral surface of bone specimen was sealed by silicone rubber to simulate the flowing situation of buffer solution flowing through Haversian canal; while unsealed condition was used to simulate the situation of buffer solution flowing through Haversian canal and bone canalicules of osteon whose specimen surface was split at the same time. Result showed that corresponding to loading rates of 26, 36, 60, 180 and 360 kPa/s, when the lateral surface was sealed, the stable values of streaming potential respectively were （0.29 ±0.09）,（0.24 ±0.06）,（0.21 ±0.05）,（0.19 ±0.05）and（0.16 ±0.04）mV. Under unsealed condition, the streaming potential was （0.69 ±0.08） , （0.61 ±0.09） , （0.57 ±0. 07） , （0.51 ± 0.05 ） and（0.46 ± 0.05 ） mV, which was apparently higher than that under sealed condition （ P 〈 0.05 ）. Besides, the difference between the potentials reflects that the produced streaming potential when the buffer solution was flowing through bone canalicules was higher than that when the buffer solution was flowing through Haversian canal. Based on the microstructure of bone and in consideration of bone cells are mainly distributed near the bone canalicules, the experimental results provide the basis for study of streaming potential and bone remodeling.