Chiropractic is focused on the diagnosis, treatment and prevention of musculoskeletal disorders. Evidences suggest that chiropractic manipulation (CM) might exert positive effects in osteoporotic patients. Muscle tension changes during CM could account in part for these beneficial bony effects. The objective of this study was to evaluate the effects of CM on bone structure and skeletal muscle in ovariectomised rats. Sham-operated (Sh; n=10) and ovariectomised (OVX; n=15) Sprague-Dawley rats (6 months-old) were submitted (M group) or not (NM group) to CM using the activator adjusting instrument model 5 (ACT5) as follows: Force 1 setting was applied onto the tibial tubercle of the right hind limb of M-rats (true CM; tM), at an angle of approximately 90°, from medial to lateral; the corresponding left hind limb received a sham CM consisting of firing the ACT5 in the air and then slightly touching the tibial tubercle. These procedures were repeated 3 times a week for 6 weeks. BMD and BMC in long bones and L3-L4 vertebrae were determined in the living subjects. After euthanasia, femora and tibiae were removed for μCT analysis; Soleus, quadriceps and tibial muscles were submitted to Western analysis of mechano growth factor (MGF) protein. No differences in all parameter studied were observed between NM-OVX and fM-OVX or between NM-Sh and fM-Sh groups. The decrease of BMD and BMC as well as trabecular bone impairment in the long bones of NM-OVX rats, compared to NM-Sh group, was partially reversed in tM-OVX rats. This was accompanied by higher MGF protein expression in quadriceps and anterior tibial muscle of the latter group compared with NM-OVX. Bone mass values of L3-L4 vertebrae were similar in all OVX-groups, independent of CM. These results support the hypothesis that CM may improve osteoporotic bone through a mechanism involving skeletal muscle.
Disclosure: The authors declared no competing interests. This work was supported by Real Centro Universitario Escorial-María Cristina (N/A).