Figure 1.
Schematic time line representation of the experimental design.
All animals were submitted to MRI two days after the IVD puncture and CBD (30, 60 or 120 nmol) microinjection. Animals that received CBD 120 nmol microinjection were resubmitted to MRI at the 15th day post-lesion and then to the histological analyses.
Table 1.
Histologic grading scale.*
Figure 2.
Representative histological sections of IVD.
(A) Intact disc showing well-organized fibers in the annulus fibrosus (af) with clearly defined border, and nucleus pulposus (np) comprising a significant disc area, with minimal border disruption. (B) IVD 15 days after lesion and vehicle injection showing an AF with lamellar disorganization, cavity obliteration with no NP cells and height decrease. (fm) fibrous material; sagittal sections; hematoxylin and eosin, 5X.
Figure 3.
Representative serial T2-weighted midsagittal MRI.
A and B, T2-weighted MRI obtained in four rat tail IVDs. The arrow indicates a reference body used to localize the Co7–8 disc in the image. 1 Co9–10 intact: vehicle injection; 2 Co8–9 21-gauge needle puncture: vehicle injection; 3 Co7–8 intact; 4 Co6–7 21-gauge needle puncture: CBD injection.
Figure 4.
MRI evaluation 2 days after lesion and CBD injection.
The injection of CBD 30 (A) or 60 nmol (B) did not prevent the MRI signal reduction induced by needle puncture. CBD 120 nmol injected into the punctured discs mitigates the MRI changes (C). The injection of vehicle per se caused significant changes in the MRI signal intensity of the non-puncture discs compared to the intact discs (A–C). *p<0.05 versus intact discs. # p<0.05 versus vehicle injected lesioned discs.
Figure 5.
MRI evaluation 15 days after lesion and CBD injection.
The injection of CBD 120 nmol into the punctured discs mitigates the MRI changes. The injection of vehicle per se caused significant changes in the MRI signal intensity of the non-puncture discs compared to the intact discs. *p<0.05 versus intact discs. # p<0.05 versus vehicle injected lesioned discs.
Figure 6.
Effects of CBD on histological scores 15 days after IVD puncture.
IVDs that received an injection of vehicle after needle puncture showed significant worse histological scores. CBD 120 nmol injection significantly improved histological scores of the AF. *p<0.05 versus intact discs. # p<0.05 versus vehicle injected lesioned discs.