Hughes S P, Lemon G J, Davies D R, Bassingthwaighte J B, Kelly P J
J Bone Joint Surg Am. 1979 Sep;61(6A):857-66.
In a study of a standardized fracture of the tibia in dogs, we examined the relationship between extraction of strontium-85, as measured by a multiple indicator-dilution technique, and blood flow, as determined by an iodoantipyrine-washout technique. Although the blood flow at the fracture site increased from a control value of 1.5 milliliters per 100 grams of bone per minute to a value of 6.65 milliliters per 100 grams of bone per minute at two weeks, the maximum instantaneous extraction of Sr by the fractured tibiae did not change from a value of about 0.77 of the amount injected. These results suggest that the increase in blood flow is accomplished by recruitment of capillaries, that the permeabilities of the capillary beds in the fractured tibia and in the normal tibia are similar, and that the pattern of flow in the fractured tibia remains non-uniform. The increased capillary surface area available for exchange is suggested as the reason that strontium extraction was unchanged despite the increased flow.
This study has shown that calcium is only moderately rapidly exchangeable across the capillary membrane and made available for uptake by osteoblasts and deposition in callus at the fracture site. Because calcium delivery via capillary is essential, and because capillary surface area is ordinarily increased in the region of a healing fracture, we can now see clearly that clinical treatment, in particular manipulative intervention, should be carried out in a fashion that minimizes damage to the capillary bed. The exchange processes described in this study are the same as those involved in the deposition of agents used for bone-scanning, and thus this information provides a basis for the timing of scanning studies and for their interpretation.
在一项对犬胫骨标准化骨折的研究中，我们通过多指示剂稀释技术测量了锶 - 85的摄取量，并通过碘安替比林洗脱技术测定了血流量，以此来研究两者之间的关系。尽管骨折部位的血流量在两周时从每100克骨每分钟1.5毫升的对照值增加到每100克骨每分钟6.65毫升，但骨折胫骨对锶的最大瞬时摄取量并未从注入量的约0.77改变。这些结果表明，血流量的增加是通过毛细血管的募集实现的，骨折胫骨和正常胫骨中毛细血管床的通透性相似，并且骨折胫骨中的血流模式仍然不均匀。尽管血流量增加，但锶摄取量未变，原因可能是可用于交换的毛细血管表面积增加。
本研究表明，钙通过毛细血管膜的交换速度仅为中等程度，可用于成骨细胞摄取并沉积在骨折部位的骨痂中。由于通过毛细血管输送钙至关重要，并且由于在愈合骨折区域毛细血管表面积通常会增加，我们现在可以清楚地看到，临床治疗，特别是手法干预，应以尽量减少对毛细血管床损伤的方式进行。本研究中描述的交换过程与用于骨扫描的药物沉积过程相同，因此这些信息为扫描研究的时间安排及其解读提供了依据。
