Effect Of Specific Knockout Of Rictor Gene In Mouse Macrophage On Disc Degeneration

Objective: To study the effect of Rictor gene on intervertebral disc degeneration in mice.Observe the changes of intervertebral disc tissue morphology and structure of specific macrophage Rictor gene knockout mice and WT mice after intervertebral disc degeneration,and study the mechanism of rapamycin in intervertebral disc degeneration.Methods: WT mice and Rictor knockout mice were divided into WT group and Rictor KO group with eight mice in each group.In both groups,a model of coccygeal degeneration was established by using 31 G standard needle to puncture Co4-5 intervertebral disc through the annulus fibrosus at a magnification of 15 times.At week 8 after the establishment of the model,coccygeal specimens were taken for Micro CT radiography to detect the degeneration of responsible vertebrae,and HE staining,crocean staining and col Ⅱ collagen immunohistochemistry were used to detect the morphological and structural changes of the degenerative intervertebral disc.Meanwhile,immunofluorescence and q-pcr were used to detect the polarization of local immune cells in the degenerative intervertebral disc.Rapamycin was used to inhibit mTOR pathway and observe its therapeutic effect in intervertebral disc degeneration.Results: Micro CT examination showed that the disc index of the Rictor KO group was lower than that of the WT group,and there was a statistical difference(P < 0.05).The results of HE staining and saffron solid green staining showed that the disc degeneration in the Rictor KO group was more serious than that in the WT group,and the disc histological grading score was statistically significant(P < 0.05).The immunohistochemical results of col Ⅱ collagen showed that the level of intervertebral disc degeneration in the Rictor KO group was higher than that in the WT group,and the col Ⅱ collagen staining area was statistically significant.Immunofluorescence results showed that,compared with WT group,m1-type macrophages were increased in Rictor mice while m2-type macrophages were decreased.q-pcr results showed that,compared with the WT group,the inflammatory factors associated with m1-type macrophages increased in the Rictor KO group,while those associated with m2-type macrophages decreased.After rapamycin treatment,Micro CT examination of mice showed significant reduction in intervertebral disc degeneration,with statistical significance between groups.Conclusion: The specific knockout of Rictor gene can inhibit the polarization of macrophages to m2-type macrophages,increase the release of inflammatory factors in mouse intervertebral disc degeneration,and aggravate the coccygeal degeneration in mice.Rapamycin treatment control disc degeneration in mice.