Effect of Treadmill Training on Recovery of Lower Urinary Tract and Locomotor Function following Incomplete Spinal Cord Injury in Adult Rats

摘要

Inability to walk and void efficiently after spinal cord injury (SCI) is associated with secondary health problems that affect quality of life. Individuals with paraplegia rate return of bladder function as one of their top priorities. Recently, studies have begun to investigate the recovery of bladder function after SCI. Additionally, several studies have shown improvements in locomotor function after SCI in human and animal models, however there is a gap of studying the correlation of temporal pattern of recovery of bladder and locomotor function after SCI. The aim of this research was to study the correlation of the temporal pattern of recovery of locomotion and lower urinary tract (LUT) function following treadmill training (TT) after SCI in a rat model.;Following a period of acclimatization, all rats (n = 19) underwent a moderate SCI (210kd) at the thoracic 8 vertebral level. Two weeks following SCI, rats were randomly divided into control (n = 9, SCI + no TT) and experimental groups (n = 10, SCI + TT). TT continued for 5X/week for 10 weeks where assistance was provided to trunk and hindlimbs where needed. To investigate LUT function, we developed a novel, minimally invasive method called serial transurethral cystometry (STUC). STUC allowed for the repeated measurement of bladder and external urethral function (EUS) function under ketamine-xylazine anesthesia. Measures of LUT from awake rats were taken by placing them in metabolic chambers overnight. Locomotor function was assessed weekly by using behavioral tests including the BBB, horizontal ladder and catwalk gait analysis.;Serial transurethral cystometry is a minimally invasive and effective method for serial measurements of LUT function. Our results show improvements in locomotor function (weight supported plantar stepping, coordination, base of support and paw placements) between 3--6 weeks of TT. There were no further improvements beyond 6 weeks of TT. LUT function shows a trend of better recovery of bladder function in the trained group. The EUS function, in particular the relaxation time (silent periods) showed robust recovery in the trained group. We found that recovery of LUT and locomotor are correlated, both have somatic innervation and the circuitry for both is located in the rostral lumbar spinal cord. Our findings show that TT can be an effective rehabilitation tool not only to improve walking function, but concomitant bladder function as well.