Experimental rat model for cervical compressive myelopathy

Abstract

Previously, a rat model of chronic compressive myelopathy that uses a water-absorbing polymer inserted under a spinal lamina was reported. However, the best size and coefficient of expansion of the polymer sheet have not yet been established. The aim of the present study was to optimize these properties in an ideal rat model of cervical compressive myelopathy. Thirty rats were used in this study. A sheet of water-absorbing polymer was inserted under the cervical laminae. Rats were divided randomly into five experimental groups by the expansion rate (350 or 200%) and thickness (0.5 or 0.7 mm) and the control. After the surgery, the severity of paralysis was evaluated for 12 weeks. At 12 weeks after the surgery, cresyl violet staining was performed to assess the number of motor neurons in the anterior horn at the C4/C5 segment and Luxol Fast Blue staining was performed to assess demyelination in the corticospinal tract at the C7 segment. ‘Slow-progressive’ paralysis appeared at 4–8 weeks postoperatively in rat models using sheets with 200% expansion. By contrast, only temporary paralysis was observed in rat models using sheets with 350% expansion. A loss of motor neurons in the anterior horn was observed in all groups, except for the control. Demyelination in the corticospinal tract was observed in rat models using sheets with 200% expansion, but not rat models using sheets with 350% expansion. A polymer sheet that expands its volume by 200% is an ideal material for rat models of cervical compressive myelopathy.

Muscone suppresses inflammatory responses and neuronal damage in a rat model of cervical spondylotic myelopathy by regulating Drp1‐dependent mitochondrial fission

“…This study was not pre-registered. cervical spondylotic myelopathy, Drp1, mitochondrial dynamics, muscone, NLRP3 inflammasome No sample size calculations or blinding were performed; however, sample sizes were consistent with those normally used in the field (Holly et al, 2012;Ijima et al, 2017).…”

Zonisamide ameliorates progression of cervical spondylotic myelopathy in a rat model

“…In patients with CSM, motor and sensory symptoms develop slowly and progress steadily for several years 35 – 37 . To recapitulate human CSM in an animal model, we epidurally implanted a blade-shaped water-absorbing polyurethane elastomer (Aquaprene Dx) 26 underneath the C5 and C6 laminae in a rat, while keeping the laminae uncut (Fig. 1 A,B and Supplemental Fig.…”

“…We hope to note three unique features of our model. First, a 0.7-mm-thick implant has been previously used 9 , 26 , 28 . We increased the thickness of the implant to 0.8 mm to enable invariable generation of a rat CSM model.…”

“…Third, evaluation of motor deficits by the CatWalk system enabled early detection of CSM phenotypes, as has been reported by another group 34 , 38 . In contrast, evaluation of motor deficits with conventional methods require 8–17 weeks after surgery 26 , 28 . We confirmed reproducibility of CSM phenotypes in our rat model, and used our model to examine the effect of ZNS.…”

“…We used an expandable material made of a water-absorbing polyurethane elastomer (Aquaprene Dx, Sanyo Chemical Industries) 26 . The polymer sheet reached a volume of 150% over 24 h when embedded under the skin of a rat (Supplemental Fig.…”