An initial investigation into the possible influence of reactive oxygen species (ROS) in chronic nerve compression injuries and the effects of osteopathic manipulative therapy (OMT)

Introduction

Results from our lab indicate that changes in muscle morphology and function caused by nerve compression can be ameliorated by use of muscle energy OMT.

Design

In attempting to determine the mechanism by which these effects occur, we have conducted experiments to establish whether ROS, known to be generated during neural degeneration, may be involved, and whether or not OMT has its effects by decreasing or helping eliminate ROS in and around the muscle. To do so, we have compared the effects of OMT with those of the antioxidant Ginkgo biloba, a known neuroprotective compound.

Methods

Rats underwent unilateral chronic sciatic nerve compression (at 100mmHg) via suture ligation for four, six or eight weeks. Of these experimental animals, four underwent no treatment, four underwent two-times weekly OMT, four were fed Ginkgo biloba (Gb; incorporated into food pellets), and a final group of four received both OMT and Gb. As in previous experiments, OMT included both passive and active muscle energy techniques and effleurage and petrissage. All other methods were the same as previously presented. Animals were euthanized after four, six or eight weeks, and single fast-twitch extensor digitorum longus fibers were dissected and chemically demembranated. As in previous studies, we assessed fiber morphology by direct measurement, and function as the change in force generation caused by the fatigue metabolite inorganic orthophosphate (P_i; (H₂PO₄⁻)).

Results

Under all experimental conditions, there was a tendency for amelioration of the enhanced P_i sensitivity caused by nerve compression, with significant differences among the OMT groups at four, six and eight weeks, with Gb reducing muscle sensitivity to P_i to a lesser degree, and with the reduction being similar at four, six and eight weeks. Differences at four, six and eight weeks remained when OMT was combined with Gb. In all cases, the combined OMT and Gb effects were less than fully additive. OMT, but not Gb, reduced muscle atrophy.

Conclusions

Present results provide further evidence of the palliative effect of OMT, in the case of muscle morphology and function, in chronic nerve compression syndromes. Also, since the effects of OMT and Gb are not totally additive, we hypothesize that, while OMT and Gb may work via altering oxidative conditions within and around the muscle, in agreement with our previous results, OMT provides an additional ameliorative effect not related to ROS.

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