EFFECTS OF ELECTRICAL-STIMULATION ON LYMPHATIC FLOW AND LIMB VOLUME IN THE RAT

Background and Purpose. The mechanism by which electrical stimulation affects edema has not been elucidated. The purpose of this study was t o determine whether subcontraction high-voltage stimulation (SC-HVS) ( ie, electrical stimulation that did not elicit a visible contraction) applied to the right hind limbs of rats would (1) alter the rate of ly mphatic uptake of injected albumin labeled with Evans blue dye (AL-EBD ) and (2) affect experimentally induced edema. Subjects and Methods. T he paws of 28 anesthetized Sprague-Dawley rats (mean weight = 263 g, S D = 48 g) were injected with AL-EBD. The experimental group (n = 13) r eceived 1 hour of SC-HVS, and the control group (n = 15) received sham treatment consisting of the same treatment administered to the experi mental group but without the SC-HVS. Blood samples and volume measurem ents were obtained at intervals over a 7-hour period. Results. Analysi s of variance and post hoc testing indicated that higher amounts of AL -EBD were taken up by the lymph of the experimental group animals as c ompared with the control group animals at each time period following t he treatment. The experimental group's AL-EBD reached significance imm ediately after treatment, whereas the control group required an additi onal 4 hours. There was no significant reduction in limb volume in eit her group. Conclusion and Discussion. The SC-HVS significantly increas ed the uptake of AL-EBD by lymphatic vessels, but it did not cause a s ignificant decrease in the induced edema. The results of this study in dicate that SC-HVS has the potential to reduce edema by increasing lym phatic uptake of proteins.