Article

Transcutaneous electrical nerve stimulation (TENS) can be used as a
physical therapy for spasticity, but the effects of TENS on spasticity and its
underlying mechanisms remain unclear. OBJECTIVE: The purpose of this study was to
test the effects of TENS on spasticity and the role of activated microglia as
underlying mechanisms of TENS treatment for spasticity in rats with a 50-mm
contusive spinal cord injury (SCI). METHODS: A spinal contusion was made at the
T12 spinal segment in adult male Sprague-Dawley rats using the NYU impactor.
Behavioral tests for motor function were conducted before and after SCI and
before and after TENS application. To assess spasticity, the modified Ashworth
scale (MAS) was used before and after SCI, high-frequency (HF)/low-frequency (LF)
TENS application at 3 different intensities (motor threshold [MT], 50% and 90%
MT) or minocycline administration. Immunohistochemistry for microglia was
performed at the lumbar spinal segments. RESULTS: Motor recovery reached a
plateau approximately 28 days after SCI. Spasticity was well developed and was
sustained above the MAS grade of 3, beginning at 28 days after SCI. HF-TENS at
90% MT significantly alleviated spasticity. Motor function did not show any
significant changes with LF- or HF-TENS treatment. HF-TENS significantly reduced
the proportion of activated microglia observed after SCI. Minocycline, the
microglia inhibitor, also significantly alleviated spasticity with the reduction
of activated microglia expression. CONCLUSIONS: These results suggest that
HF-TENS at 90% MT alleviates spasticity in rats with SCI by inhibiting activated
microglia.
CI - (c) The Author(s) 2014.

Langue : ANGLAIS