Effects of deep vs. superficial stimulation of acupuncture on capsaicin-induced edema. A blind controlled study in rats.

The modality of needle stimulation in acupuncture is part of the concept of the iintensityi of the stimulation, a variable indicating the idosagei of the treatment administered. In this study we intend to compare the effect of superficial and deep needle insertion in the leg ipsilateral or contralateral to the paw treated with capsaicin. Testing was carried out on 100 male Sprague-Dawley rats weighing 120-140 g, divided into 5 groups according to the treatment received. Group 1 [20 animals] was kept as control; Group 2 [20] received ipsilateral deep acupuncture stimulation; Group 3 [20] received ipsilateral superficial acupuncture stimulation; Group 4 [20] received contralateral deep acupuncture stimulation; Group 5 [20] received superficial contralateral acupuncture stimulation. Results show that both acupuncture modalities are efficient when administered ipsilaterally to the paw where capsaicin is injected, while contralaterally only deep stimulation shows a certain efficiency. It is possible to conclude that deep insertion has a greater efficiency, probably because it affects a greater number of receptors; stimulation is therefore of an intensity greater than that seen in superficial insertion.