Establishment of a rabbit model of lumbar intervertebral disc degeneration via the paraspinal approach / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a rabbit model of intervertebral disc degeneration by puncturing the anulus fibrosus through an approach between the longissimus dorsi muscle and obliquus externus abdominis.</p><p><b>METHODS</b>The L(4/5) and L(5/6) intervetebral discs of 6 New Zealand white rabbits were punctured by an 18-gauge pin in the anterolateral annular fibrosus through an approach between the longissimus dorsi muscle and the obliquus externus abdominis with the right transverse processes of L(5) and L(6) resected; the L(2/3) discs were used as the control without exposure or needle stab, and the L(3/4) discs were subjected to sham operation with the discs exposed but not punctured after resecting the right transverse process of L(4). X-ray and magnetic resonance imaging (MRI) were performed preoperatively and at the 4th week after puncture. At 4 weeks after the operation, histological and immunohistochemical analyses of the discs were carried out.</p><p><b>RESULTS</b>X-ray of the punctured discs at 4 weeks after the operation presented a significant decrease of disc height, osteophytosis formation, and end-plate stiffness; an obvious decrease of signal intensity on T(2)-weighted images was found in the puncture group but not in the control or sham-operated groups. Gross morphological inspection showed atrophy of the nucleus pulposus, which became loose, soft, and fragile with a light yellow color. Histological and immunohistochemical analyses showed a significant decrease of notochordal cells and type II collagen in the nucleus pulposus in the puncture group as compared to the control and sham-operated groups.</p><p><b>CONCLUSION</b>Puncture through the approach between the longissimus dorsi muscle and the obliquus externus abdominis allows the establishment of a reliable animal model for studying intervertebral disc degeneration.</p>

Lithium chloride combined with human umbilical cord blood mesenchymal stem cell transplantation for treatment of spinal cord injury in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effects of lithium chloride combined with human umbilical cord blood mesenchymal stem cell (hUCB-SCs) transplantation in the treatment of spinal cord injury in rats.</p><p><b>METHODS</b>Eighty female SD rats with complete T9 spinal cord transaction were randomized into 4 groups (n=20), namely the control group (group A), lithium chloride group (group B), hUCB-SCs group (group C) and hUCB-SCs(+) lithium chloride group (group D). On days 1 and 3 and the last days of the following weeks postoperatively, the motor function of the hindlimb of the rats were evaluated according to the BBB scores. At 8 weeks, all the rats were sacrificed and the spinal cords were taken for morphological observation. The spinal cord tissues at the injury site were observed with Brdu nuclear labeling to identify the survival and migration of the transplanted SCs. The regeneration and distribution of the spinal nerve fibers were observed with fluorescent-gold (FG) spinal cord retrograde tracing.</p><p><b>RESULTS</b>Brdu labeling showed that the transplanted hUCB-SCs survived and migrated in the spinal cord 8 weeks postoperatively in groups C and D. FG retrograde tracing identified a small amount of pyramidal cells that migrated across the injury site in groups C and D. The BBB scores of the hindlimb motor function 8 weeks postoperatively were 4.11∓0.14, 4.50∓0.15, 8.31∓0.11 and 11.15∓0.18 in groups A, B, C and D, respectively.</p><p><b>CONCLUSION</b>Lithium chloride can promote the survival and differentiation of hUCB-SCs into neural cells at the injury site. Lithium chloride combined with hUCB-SCs transplantation may accelerate functional recovery of the hindlimbs in rats with complete transection of the spinal cord.</p>

Correlation between increased spinal cord signal intensity on T2-weighted MRI and clinical prognosis of compressive cervical myelopathy / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the correlations between increased spinal cord signal intensity on magnetic resonance images (MRI) and the clinical prognosis of compressive cervical myelopathy.</p><p><b>METHODS</b>Sixty-six patients with cervical spondylotic myelopathy underwent surgeries through the anterior approach. In all the patients, the diagnoses were established on the basis of both neurological examination and MRI findings that showed spinal cord compression. The patients were divided into two groups according to preoperative MRI, namely isointense MRI T1/T2 signal group and iso/hyperintense MRI T1/T2 group. The JOA scores of the patients were evaluated before and at 6 and 12 months after the operation.</p><p><b>RESULTS</b>The patients were followed up for 12 to 38 months after the operation (mean 21 months), and no statistically significant difference were found in the pre- and postoperative JOA scores between the two groups (P>0.05).</p><p><b>CONCLUSION</b>The peoperative hyperintense signals on T2 weighted MRI does not correlate to the prognosis of patients with compressive cervical myelopathy, who may also have favorable clinical outcomes after the operation.</p>