H reflex restitution and facilitation after different types of peripheral nerve injury and repair.
This study addresses the restitution of monosynaptic H reflex after nerve injuries and their role in the recovery of walking. Adult rats were submitted to sciatic crush, complete section repaired by aligned or crossed fascicular suture, or an 8-mm resection repaired by autograft or tube repair. The sciatic nerve was stimulated proximal to the injury site and the M and H waves were recorded from gastrocnemius (GCm) and plantar (PLm) muscles at monthly intervals during 3 months postoperation. Walking track tests were also carried out and the sciatic functional index (SFI) calculated to assess gait recovery. The M and H waves reappeared in all the animals at the end of the follow-up. The H/M amplitude ratio increased during the first stages of regeneration and tended to decrease to control values as muscle reinnervation progressed. However, final values of the H/M ratio for the PLm remained significantly higher in all the groups except that with a nerve crush. The walking track pattern showed an appreciable recovery only after crush injury. Final SFI values correlated positively with the M wave amplitude and negatively with the H/M ratio. In conclusion, H reflex is facilitated after peripheral nerve injury and regeneration and tends to return to normal excitability with time. Changes in the H reflex circuitry and excitability correlated positively with the deficient recovery of walking pattern after severe nerve injury.
Valero-Cabré
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Department of Cell Biology, Physiology and Immunology, Faculty of Medicine, Universitat Autònoma de Barcelona, 01893 Bellaterra, Spain.
Navarro
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D000818:Animals; D005260:Female; D005684:Gait / Q000502:physiology; D006181:H-Reflex / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology; D009409:Nerve Crush; D009416:Nerve Regeneration / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology; D010243:Paralysis / Q000503:physiopathology* / Q000534:rehabilitation / Q000601:surgery; D059348:Peripheral Nerve Injuries; D010525:Peripheral Nerves / Q000503:physiopathology* / Q000601:surgery; D010523:Peripheral Nervous System Diseases / Q000503:physiopathology* / Q000534:rehabilitation / Q000601:surgery; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*; D012584:Sciatic Nerve / Q000293:injuries / Q000503:physiopathology / Q000601:surgery; D012684:Sensory Thresholds / Q000502:physiology; D016896:Treatment Outcome