Intrinsic locomotor outcome in dorsal transection of rat spinal cord: predictive value of minimal incision depth

Abstract

Study design: Experimental, prospective, blinded, animal study. Objectives: Subtotal transection models in rodents are widely used in spinal cord injury (SCI) research. In this model, we investigate the effect of the dorso-ventral incision depth (ID) of the spinal cord on functional locomotor outcome using the Basso, Beattie, Bresnahan (BBB) scale. We introduce the minimal incision depth (ID min ) and the average lesion depth (ID mean ) as reliable, fast and easily available predictive parameters for intrinsic locomotor function. Setting: Tuebingen, Germany. Methods: Dorsal over-hemisection at the level of T8 was performed in male Lewis rats. Functional outcome 4 weeks after SCI and histological analysis of the lesion were studied and correlated in 36 animals. Animals reaching weight support (BBBX9) were considered as having reached functional recovery. Data analysis was performed in linear (ordinary least squares; OLS) and nonlinear (logistic) regression models for correlation of histological parameters and functional outcome. Results: BBB scores revealed a strong correlation with ID mean and ID min , showing a higher value in predicting functional outcome for the latter parameter. Based on logistic regression analysis, animals with an ID min of 69% would have a 95% probability of reaching weight support.Conclusion: These results demonstrate that histological analysis is crucial when functional outcome parameters are used in the dorsal over-hemisection SCI model. A simple and feasible histological evaluation can reliably predict spontaneous functional locomotor recovery in dorsal transection models and could provide a simple tool to identify treatment effects of new experimental therapeutic approaches.

Hemisection spinal cord injury in rat: The value of intraoperative somatosensory evoked potential monitoring

“…As noted in prior studies of transection and contusion SCIs, the amount of damaged tissue and pathways in animal models of spinal cord injury is associated with functional outcomes and signal conduction (Basso et al, 1995; Brechtel et al, 2006; Zhang et al, 2008). Our study provides additional evidence for the association between amount of injured tissue and performance on functional outcome measures in rats.…”

“…This incision can be used to apply either complete transection or incomplete transection (hemisection). To date a variety of hemisection-type injuries have been used including the lateral hemisection and dorsal hemisection (Brechtel et al, 2006; Fouad et al, 2000; Goldshmit et al, 2008; Ying et al, 2005). However, due to the technical difficulty of a partial cut, there is the possibility of inconsistencies in the injuries from one animal to the next.…”

“…However, due to the technical difficulty of a partial cut, there is the possibility of inconsistencies in the injuries from one animal to the next. It has been noted that the amount of injured cord is related to functional recovery (Basso et al, 1995; Brechtel et al, 2006). Therefore, to ensure consistent injuries and homogenous groups to study, it would be valuable to designate a tool to monitor the extent of injury when it occurs.…”

Polylaminin, a polymeric form of laminin, promotes regeneration after spinal cord injury

“…The observation that a significant functional improvement was obtained with a relatively mild type of injury prompted us to test the effect of polyLM on more severe lesions. First we used partial dorsal section (24), in which ∼80% of the cord tissue was sectioned in the dorsal‐ventral direction (Fig. 1).…”

IKK‐β‐mediated myeloid cell activation exacerbates inflammation and inhibits recovery after spinal cord injury

“…Luxol fast blue staining was performed to calculate lesion volume as previously described 31. Images of the stained sections were taken under microscope (Axiovert200, Carl Zeiss, Munchen, Germany) and the lesion size (x–y stage) was calculated using the Axiovision 4.8 image program.…”