Date of Award
Master of Science (MS)
Bosio, Jose A.
Introduction: Extracorporeal shock wave (ESW) is low frequency high-pressure wave, regularly used to destroy calcifications e.g. kidney stone. Recent evidence shows that ESW produces micro-cracks in the bones of horse legs. As micro-cracks in bone can lead to an increased rate of bone turnover (remodeling), we hypothesize that proper application of ESW will increase bone turnover rate through generating micro-cracks in bone.
Materials and Methods: To test our hypothesis, we used a mouse calvaria bone organ culture model and explored the effects of ESW on bone tissues ex vivo. The calvaria bone pieces were collected from 3 days old C57BL/6 neonatal mice and cultured in 10% FBS supplemented DMEM. After dissection, each quadrant (1/4) of calvaria was randomly assigned into one control and three experimental groups which were subjected to a single dose of 2000 shocks of 3 energy levels of ESW i.e. low (0.1mJ/mm², 6 Hz), medium (0.25mJ/mm², 4 Hz), and high (0.5mJ/mm², 3 Hz,) doses, respectively. After ESW stimulation, the bone tissues were further cultured for 1 week and fixed in 10% formalin. The same experiment was repeated three times (n=3). The bone samples were (1) examined by using a customized radiographic analysis program to measure the bone microdensity, and (2) demineralized and processed to undergo H&E staining to observe the cellular changes histologically.
Results: Radiographically the mid dose group exhibited a higher microdensity but not statistically significant (P > 0.05) compared to the other two ESW and the control groups. Histologically, some empty osteocytic lacunae exhibited in all the three dose ESW groups, with nearly all osteocytes disappeared in the high dose group. Hypertrophy of osteoblasts was mainly found in the low dose group. No microcracks were observed on all the H&E staining tissue slides. Histological differences cannot be calculated statistically mainly due to the high heterogeneity of the samples.
Conclusion: Although not statistically significant, the mid dose ESW group seems to gain bone microdensity. Due to the lack of statistical differences, definite conclusions cannot be drawn, leaving further endeavors be put on this topic.