Effects of electromagnetic therapy on proprioception in a rodent animal model of rheumatoid arthritis

Introduction This study aimed primarily to investigate the effect of a PEMF on proprioception in terms of mechanoreceptor number and function and secondarily to assess the gait quality (sciatic function index) and arthritis severity (paw volume and body weight) in adjuvant-induced arthritis (AIA) RA model. Methods Twenty-eight healthy adult male Wistar rats were randomly divided into 3 groups: (I) RA experimental model treated with a PEMF (10 animals), (II) positive control (10 animals), and (III) negative control (8 animals). Group I was exposed to a PEMF (0.3 mT 1 h/day for 2 weeks), while Groups II and III were placed in the same setup, except that the PEMF was turned off. The proprioceptive function [as tactile response (TR) / hopping response (HR) / forelimb placing test (FPT)], paw volume (PF), and mechanoreceptor numbers were then tested. Results There was a significant preservation of mechanoreceptor numbers and proprioception in group I compared to group II, as follows: the number of Ruffini corpuscles mechanoreceptors ( p = 0.007) and TR on days 9 and 14 ( p = 0.002, 0.012, respectively) with no significant difference compared to group III. Also, PV decreased significantly in group I relative to group II ( p = 0.01) with no significant difference for group III. Conclusions PEMF significantly preserved proprioception receptors and function and decreased inflammation severity in the AIA-RA model.