Effects of Manual Acupuncture with Sparrow Pecking on Muscle Blood Flow of Normal and Denervated Hindlimb in Rats

Abstract

Introduction In clinical practice, it has been thought that acupuncture might serve to wash out pain-generating metabolic end-products by improving blood circulation in muscles. We investigated the effects of manual acupuncture (MA) on muscle blood flow (MBF) of normal and denervated hindlimbs in rats. Method Sprague-Dawley rats (n=100) anaesthetised with urethane (1.2g/kg ip) were used. Manual acupuncture with sparrow pecking (SP) at different doses (1, 10 or 30 pecks) was given to the right ventral hindlimb muscles (tibial anterior and extensor digitorum longus muscles) or the right dorsal hindlimb muscles (gastrocnemius, plantaris and soleus muscles). MBF with or without MA was measured using the radiolabelled microsphere technique. The blood pressure was recorded through the right common carotid artery until MBF measurement started. Denervation of hindlimb was conducted by cutting the sciatic and femoral nerves. Results In normal rats, significantly increased MBF after MA were observed only in muscles which were penetrated by an acupuncture needle. The size of the increase depended on the number of times of pecking and seemed to be sustained at least until 60 minutes after MA. However, the increase was observed after both acute and chronic denervation. On the other hand, the mean arterial blood pressure (MAP) did not change significantly before, during or after MA. Conclusion These results suggest that MA could increase muscle blood flow locally in a dose-dependent manner and that this increase may be caused by local vasodilators, as well as the axon reflex. A further study is needed to elucidate the mechanism.