Effect of high-voltage electrical stimulation on the albumin and histamine serum concentrations, edema, and pain in acute joint inflammation of rats

BACKGROUND The mechanism by which high-voltage electrical stimulation (HVPC) acts on edema reduction is unknown. OBJECTIVE To assess the effect of HVPC with negative polarity (-) applied to the ankle of rats with acute joint inflammation. METHOD Sixty-four rats were divided into four groups (n=16): inflamed+HVPC(-), 0.03 mL application of ι-carrageenan (3%) to the tibiotarsal joint plus HVPC(-); inflamed+HVPC placebo, carrageenan application and HVPC placebo; normal+HVPC(-), HVPC application(-); and normal control, no intervention. The HVPC(-) 100 Hz at a submotor level was applied daily for 45 min on three consecutive days. The variables were pain, hind-foot volume, and serum histamine and albumin assessed before and during the 48 hours following inflammation. The variables were compared using the t test, one-way ANOVA, nested ANOVA for repeated measures, and the post hoc Bonferroni test. Analysis of covariance was applied to adjust the effects of HVPC(-) by measurements of pain, inflammation, albumin, and histamine at 24 h, and the final weight was compared to the other groups. The significance level was set at p<0.05. RESULTS There were no differences between the inflamed+HVPC(-) and inflamed+HVPC placebo groups in terms of pain or edema (p>0.05). Albumin was reduced in the groups that received the intervention, but there was no differences between them. There was only a 24 hour increase in histamine with the normal+HVPC(-) (p=0.0001) and inflamed+HVPC placebo groups (p=0.01) compared to the normal control group. CONCLUSIONS The results of the present study suggest that HVPC(-) with the parameters employed did not reduce pain or edema and did not change serum albumin or histamine levels,, which indicates the inability of this resource to have a positive effect when treating treat acute joint inflammation.