Spontaneous recovery of hindlimb movement in completely spinal cord transected mice: a comparison of assessment methods and conditions

Abstract

Study design: To compare results obtained with a variety of locomotor rating scales in Th9/10 spinal cord transected (Tx) mice. Objectives: To assess spontaneous recovery with a variety of rating scales to find the most sensitive methods for assessing recovery levels in Tx mice and differences associated with gender and condition. Setting: Laval University Medical Center, Neuroscience Unit & Laval University, Department of Anatomy and Physiology, Quebec City, Quebec, Canada. Methods: Scales including the Basso, Beattie and Bresnahan (BBB), the Basso Mouse Score (BMS), the Antri, Orsal and Barthe (AOB), the Motor Function Score (MFS) and the Averaged Combined Score (ACOS) were used to assess, in open-field and treadmill conditions, spontaneous locomotor recovery in male and female Tx mice. Results: The ACOS scale revealed a progressive increase of spontaneous recovery during 5-weeks post-Tx. The other methods detected a progressive increase for the first 2-3 weeks postTx without any significant progress in weeks 4 and 5. Generally, scores obtained with each method were nonsignificantly different between males and females or between open-field and treadmill conditions. Conclusion: These results further confirm the existence of a limited but significant increase of locomotor function recovery, occurring without intervention, in Tx animals. Although each method could detect small levels of recovery, the ACOS method was discriminative enough to detect progressive changes up to 5 weeks post-Tx. In conclusion, the ACOS rating scale was the most discriminative method for assessing the spontaneous return of hindlimb movements found in Tx mice, both in open-field and treadmill conditions.

Non-assisted treadmill training does not improve motor recovery and body composition in spinal cord-transected mice

“…[6][7][8] Here, Tx mice from the untrained group displayed hindlimb movements corresponding to AOB scores no greater than '1' (Figure 1a). Similar results were found in the trained mice.…”

“…1,2 In fact, even without pharmacological aids, regular TT assisted with a weight-supporting harness and/or tail or sexual organ pinching can enable the expression of involuntary 'reflex' stepping in low-thoracically spinal cord-transected (Tx) animals. [3][4][5] However, without assisted training, some spontaneously occurring small amplitude hindlimb movements were also shown to progressively occur a few weeks post-Tx in untrained Tx mice, [6][7][8] suggesting that basic spontaneous sublesional plasticity and spinal learning events may occur even in the absence of assisted training. Untrained Tx mice were also found to undergo significant changes in body compositionFfor example, body weight (À24%) and soleus fibre properties (À32% in mass and maximal force) within a few days postTx, 9 whereas assisted TT was found to partially prevent muscular property changes in Tx cats and rats.…”

“…In this study, we determined to examine the effect of TT alone (without assistance) on locomotor recovery. This experimental protocol was driven by the idea that progressively occurring motor and locomotor-like movements displayed typically in untrained Tx animals, [6][7][8] if combined with the stimulation provided by the moving treadmill belt, may suffice to further promote locomotor function recovery. However, as shown here, non-assisted TT did not enable the , respectively.…”

“…5 We also used a semiquantitative assay called Average Combined Score (ACOS) that has been developed in our laboratory for 'live' semiquantitative assessment of hindlimb movements in Tx rodents. [6][7][8] ACOS is designed to assess non-locomotor movements (NLM, number min À1 ), locomotor-like movements (LM, number min…”

Варіативність Кореляції Рівня Функції Та Спастичності Паретичної Кінцівки За Різного Перебігу Відновного Процесу На Моделі Спінальної Травми

“…Попри значний прогрес у цьо-му напрямку [20][21][22][23], недостатньо вивченими за-лишаються питання щодо динаміки спастичнос-ті при різноманітних видах експериментальної травми спинного мозку [24][25][26][27][28][29], її співвідношен-ня з динамікою відновлення функції. Останній момент, попри вдавану очевидність, у сучасних експериментальних роботах, присвячених скру-ЕКСПЕРИМЕНТАЛЬНІ ДОСЛІДЖЕННЯ пульозному аналізу клініки однотипних варіан-тів спінальної травми, не висвітлений [30][31][32][33][34][35][36]. Ряд даних вказує на паралелізм механізмів спастич-ності та відновлення функції мотонейронів спин-ного мозку після спінального шоку [37], на ран-ніх етапах спінальної травми ці два механізми, най імовірніше, ідентичні; нейропластичний про-цес на цих термінах спінальної травми має амбі-валентну результативність -сприяючи відновлен-ню чутливості мотонейронів до вцілілих супрас-пінальних впливів, створюються передумови для формування різноманітних форм спінальної дис-рефлексії, у тому числі спастичності.…”