Empirical Study Of Interleukin-18 Effects In The Rabbit Lumbar Intervertebral Disc

Objective:To investigate the in vivo effects of IL-18 on content of aggrecan,changes of structure and the expression of MMP-3 on intervertebral disc.Methods:Seventy-two health rabbits were randomly divided into three groups,including control group(no intervention of the disc),IL-18 group(IL-18 injectde into the intervertebral discs)and Nacl group(Nacl injectde into the intervertebral discs).Used L4/5 intervertebral disc were exposed surgically,0.9%NaCl(lul)and various concentrations (10ng/ul,20ng/ul and 40ng/ul) of IL-18(1ul) were respectiyely injected into L4/5 intervertebral discs.HE-staining,aggrecan content neasuring and expression of MMP-3 on intervertebral disc were done when the animals were killed at the third and sixth week..Results:①The HE-staining showed that, with the increase of IL-18, the amount of nucleus pulposus cells decreased, reticular framework was broken down, vacuole shapedisappeared and oval nucleolus of cells became multi-shape.②Three weeks,Content of aggrecan has not changed apparently in control and Nacl group, but in the experiment groups rapid decline (15.72%～43.78%,P<0.001)was evidenced.Six weeks, Content of aggrecan in Nacl group and experiment groups decline(P<0.05), and experiment groups decline were more correlative with the dose of IL-18(P<0.05).③In IL-18 groups,the MMP-3 masculine cells had homogeneous distribution puncti form moth patch and were increase with the concentrations and the time(P<0.05). Three weeks,there was little expression of MMP-3 in control and Nacl group,but,six weeks the expression of MMP-3 in Nacl group increase(P<0.05).Conclusion:IL-18 injectde into the intervertebral discs can lead to decline of aggrecan and morphological changes in the nucleus pulposus, which were related with time and dose of IL-18 adminstration.