Functional electrical stimulation as a safe and effective treatment for equine epaxial muscle spasms: Clinical evaluations and histochemical morphometry of mitochondria in muscle biopsies

Abstract

Functional Electrical Stimulation (FES) has been used extensively over several decades to reverse muscle atrophy during rehabilitation for spinal cord injury patients. The benefits of the technology are being expanded into other areas, and FES has been recently utilized for injury rehabilitation and performance enhancement in horses. Six retired horses (age from 10 to 17 yrs) that had been previously used mainly for dressage riding were selected for this study. Clinical evaluation found epaxial muscle spasms in all horses with minimal to no pelvic extension when manually palpated. FES treatments were performed on the sacral/lumbar region 3 times per week for a period of 8 weeks, obtaining a total of 22 treatments per horse. The Modified Ashworth Scale for grading muscle spasms found a one grade improvement after approximately four FES treatments, indicating improved functional movement of the sacral/lumbar region, supporting the evidence by clinical palpations that a reduction in epaxial muscle spasms occurred. Skeletal muscle biopsies Pre and Post FES treatments were obtained from the longissimus lumborum muscle. Cryosections were stained with a Hemotoxylin-Eosin (H-E), and nicotinamide adenine dinucleotide tetrazolium reductase reaction (NADH-TR). The eventual size change of the muscle fibers were evaluated by morphometry in the H-E and NADH-TR stained cryosections, while in the NADH-TR slides the histochemical density and distribution of mitochondria were also determined. The main results of the morphometric analyses were: 1) As expected for the type of FES treatment used in this study, only a couple of horses showed significant increases in mean muscle fiber size when Pre- vs Post-FES biopsies were compared; 2) In the older horses, there were sparse (or many in one horse) very atrophic and angulated muscle fibers in both Pre- and Post-FES samples, whose attributes and distribution suggests that they were denervated due to a distal neuropathy; 3) The hypothesis of generalized FES-induced muscle fiber damage during epaxial muscle training is not supported by our data since: 3.1) Denervated muscle fibers were also present in the Pre-FES biopsies and 3.2) Only one horse presented with several long-term denervated muscles fibers Post-FES; 4) Preliminary data indicate an increased density and distribution of mitochondria in Post-FES biopsies, suggesting that the clinical improvements in the FES treated horses may be related to daily increased muscle contraction and perfusion induced by FES training. In conclusion, FES in horses is a safe treatment that provides clinical improvements in equine epaxial muscle spasms.

Biology of muscle atrophy and of its recovery by FES in aging and mobility impairments: roots and by-products

“…7 B ). 23 It is interesting to note that, in recent observations comparing young and very old (30 months) rat muscles (EDL, soleus and diaphragm) subjected to neurectomy, 24 we found that the abundance of subsarcolemmal mitochondria decreases with age and even more so after one week of denervation, whatever the animal age (manuscript in preparation). Feliciano Protasi and others have shown very interesting data concerning the structural relationships of mitochondria with triads in the intermyofibrillar spaces.…”

“…Indeed, only one horse presents with obvious evidence of post-FES muscle damage (foci of severe muscle fiber atrophy) whereas the other 5 horses, which had the same type and amount of electrical stimulation, display only scanty evidence of muscle atrophy (possibly resulting from denervation) in both pre- and post-stimulation biopsies. 23 …”

Mieloencefalite Protozoária Equina: Relato De Caso

“…Em consonância a terapia, foi realizada a estimulação elétrica funcional (FES) para fortalecimento muscular do equino. Essa modalidade de fisioterapia tem sido usada como um meio para reduzir ou reverter a atrofia muscular, além de obter uma recuperação funcional em equinos com lesão medular (RAVARA et al, 2015). Seu uso foi eficaz, e, após 30 dias de treinamentos alternados com duração de 20 minutos, o animal apresentou melhora na atrofia muscular (Figura 1B) e em seu desempenho atlético, conseguindo realizar as atividades a que foi destinado, principalmente o salto com obstáculos.…”

The ischemic model of chronic muscle spasm and pain

“…8 Work by Ugo Carraro found similar changes in skeletal muscle that had been in a state of chronic spasm. 9 Chronic spasm of skeletal muscle, in a similar way as found in cardiac muscle, induces a state of chronic ischemia. He showed reversibility of the light microscopy structural changes with therapy of the chronic spasm.…”