Optimization of a rat lumbar IVD degeneration model for low back pain

Abstract

Introduction: Intervertebral disc (IVD) degeneration is often associated with low back pain and radiating leg pain. The purpose of this study is to develop a reproducible and standardized preclinical model of painful lumbar IVD degeneration by evaluation of structural and behavioral changes in response to IVD injury with increasing needle sizes. This model can be used to develop new therapies for IVD degeneration.Methods: Forty-five female Sprague Dawley rats underwent anterior lumbar disc needle puncture at levels L4-5 and L5-6 under fluoroscopic guidance. Animals were randomly assigned to four different experimental groups: needle sizes of 18 Gauge (G), 21G, 23G, and sham control. To monitor the progression of IVD degeneration and pain, the following methods were employed: μMRI, qRT-PCR, histology, and biobehavioral analysis.Results: T1-and T2-weighted μMRI analysis showed a correlation between the degree of IVD degeneration and needle diameter, with the most severe degeneration in the 18G group. mRNA expression of markers for IVD degeneration markers were dysregulated in the 18G and 21G groups, while pro-nociceptive markers were increased in the 18G group only. Hematoxylin and Eosin (H&E) and Alcian Blue/ Picrosirius Red staining confirmed the most pronounced IVD degeneration in the 18G group. Randall-Selitto and von Frey tests showed increased hindpaw sensitivity in the 18G group. Conclusion:Our findings demonstrate that anterior disc injury with an 18G needle creates severe IVD degeneration and mechanical hypersensitivity, while the 21G needle results in moderate degeneration with no increased pain sensitivity. Therefore, needle sizes should be selected depending on the desired phenotype for the pre-clinical model.

Advanced Glycation End Product Inhibitor Pyridoxamine Attenuates IVD Degeneration in Type 2 Diabetic Rats

“…T2-weighted µMRI analysis demonstrated a reduction in NP hydration at 8 weeks post-surgery compared to pre-surgical and uninjured IVDs in both the ZDSD and SD groups (Figure 2). This successful induction of IVD degeneration in previously healthy SD rats using an 18G needle was similar to that done in previous studies by our group and others using the same animal model [12,39]. Treatment with PM tended to attenuate the NP dehydration; however, no significant differences were detected between the ZDSD injured and ZDSD injured + PM groups ( Figure 2B).…”

“…The effect of PM on the attenuation of disc dehydration, as detected by µMRI, was limited. Our injury model induced severe disc degeneration [ 12 ]. A more moderate IVD degeneration model might be advised for future PM testing, or PM could be applied in combination with additional treatments, such as local stem cell injections, allowing for the reduction of AGE-induced processes while re-populating the IVD with healthy NP cells to replace those cells that may have become apoptotic during IVD degeneration.…”

“…Prior to surgery and at euthanasia, the rats were weighed, and their diabetic condition was evaluated by performing blood glucose tests (True Metrix, CVS Health). SD and ZDSD rats were randomly assigned to 2 different surgical groups: (1) IVD injury created with an 18G needle as previously reported [ 12 ] and (2) sham surgery only. ZDSD rats with injured IVDs were randomly assigned to a PM treatment group or a water control group.…”

“…In this study we used a rat model, since it is large enough for surgical alteration of the spinal structures and allows defined biobehavioral testing for analyzing discogenic pain [ 11 ]. In a prior study by our group, an 18-gauge (G) needle-induced IVD injury in rats led to consistent severe disc degeneration and was associated with discogenic pain [ 12 ].…”

Improving reproducibility in spine research

“… Du et al 8 report the development of an organ culture system of bovine intervertebral discs in the presence of TNF‐ɑ to test the effects of anti‐inflammatory treatment, together with translation to human IVD cells. Glaeser et al 9 utilized a needle‐puncture induced rat lumbar disc degeneration model to develop a reproducible and standardized small animal model of painful IVD degeneration that will be useful to assess the functional outcome of pain. Pain assessments in animal models have been a key limitation for developing disc therapies. Lin et al 10 compared six commercially available cellular bone matrices using athymic rat model of posterolateral fusion at the bone quality and efficiency of spinal fusion enabling the direct comparison of fusion systems within a controlled animal model. …”