Establishment of a new animal model for ischemic lumbar vertebrae.

Degeneration and ischemia of lumbar intervertebral disc has become a more and more important issue for elder people. However the mechanism for this is still known, largely due to a lack of a suitable animal model. In this study, we constructed a new animal model for the study of ischemic lumbar vertebrae. 42 New Zealand white rabbits were chosen for the study. For each rabbit, two vertebrae were used. L5 was set as the experimental group and L4 was set as the control group. Percutaneous lumbar puncture needles were applied in vertebrae adjacent to endplate for L5 and L4. For L4 1 ml saline was injected and for L5 1 ml pingyangmycin (2 mg/mL) was used. 1, 2, 3, 4, 5 weeks; 2 and 3 months after surgery, 6 rabbits at each time point were randomly chosen and underwent MRI, pathological test. The results in L5 and L4 were compared. Another 6 rabbits were used for DSA (Digital Subtraction Angiography) and vascular cast to study the length and diameters of the branches of lumbar artery. It was identified that since the third week, slightly hyperintense signal on T2-weighted image (T2WI) and fat-suppression T2-weighted image (FS T2WI) were detected. Lumbar vertebrae damage could be identified since the fourth week. Results of MRI and the size of pathological area were positively related (r=0.965, P<0.05). DSA and vascular cast could both clearly show the third level branches of lumbar artery. Our study suggested that injection of pingyangmycin via percutaneous lumbar needle could successfully induce ischemia in lumbar endplate. This method had little trauma, required a simple operation process and is highly repetitive. Besides, by vascular cast, the most important source of blood supply is the media branch of the lumbar artery. This branch could be a new therapy pathway for the degeneration of lumbar vertebrae.