| Objective To obtain rat model study of experimental lumbar degenerative intervertebral disc and observe the expression of MMP3 in disc tissue from normal lumbar disc,degenerative lumbar disc and tetracycline treat lumbar disc using immumohistochemistry and Western–bloting to explore its application value in lumbar degeneration disc and treatment with tetraxycline inhibits the development of experimental rat lumbar degenerative disc. Methods 64 S-D rats were randomly and equally divided into four groups: normal control group(Group A),degenerative control group(Group B), treatment group of small dosage of tetraxycline (Group C) and treatment group of big dosage of tetraxycline (Group D).Every group had 16 S-D rats. The rats except group A were simultaneously prepared for incising through posterior approach along spinous process, resecting below erector spinal muscle,resected the supraspinal and interspinal ligament and the posterior of the zygapophysial joint between the first and the sixth lumbar spine. After 2 weeks, the rats of group C and group D were given tetraxycline subcutaneously,among with group C with 25 mg/kg/day and group D with 50 mg/kg/day for 2 weeks. 1, 2 and 3 months after operation respectively , 4 rats chosen randomly from every group with anesthetize were examined by X ray and MRI . Lumbar discs tissues were obtain , examined by light microscopy and transmission electron microscopys and obserbved by immumohistochemistry and Western–bloting. Results To set up rat model study of experimental lumbar intervertebral disc degenerative by operating and treatment with big dosage of tetraxycline and small dosage of one. There is no special radiological characterization after operation in normal control group, and lumbar intervertebral spaces stenosis, vertebral bodies unstability and cartilage endplates were calcified exist in degenerative control group. It was obserbved in histology that cell in nucleus pulposus were recuced in degenerative control group. Under electron microscopy, living cells in the experimental nucleus pulposuses were sparse, and dead cells could often be seen. Differing from normal nucleus pulposus cells with long dendrites, the cells in the experimental nucleus pulposuses showed no dendrites or only short and small ones. The amount of cell organelles and glycogen granules reduced apparently. Collagenous fibrils appeared various kinds of degeneration including fusion, twist and calcification. Under MRI, T2 signs in degenerative control group were more than that in treatment group of small dosage of tetraxycline and treatment group of big dosage of one. T2 signs in normal control group were not chang significantly. using immumohistochemistry, The positive cell ratio of matrix metalloproteinase-3 observed in treatment group of small dosage of tetraxycline and treatment group of big dosage of one were much less than that in degenerative control group (P<0.05)and there were no significant difference between treatment group of tetraxycline and normal control group. The expression of matrix metalloproteinase-3 in treatment group of small dosage of tetraxycline and treatment group of big dosage of one were much less than that in degenerative control group by Western-bloting ( P < 0.05 ) .Conclusions The high expression of matrix metalloproteinase-3 in lumbar degenerative disc indicate that MMP-3 may be involved in lumbar disc degenerative closely. It may lie positive relationship between MMP-3 and lumbar degenerative disc. Treatment with tetraxycline—MMPs inhibitor inhibits the development of experimental rat lumbar degenerative disc in vivo. This inhibition may due to a selective blockade of elastolytic MMP-3 expression. It will provide the theory's and research's evidence for delaying and inhibiting lumbar degenerative disc occurr and develop. |
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