| Objective:The aim of this study was to investigate the morphological changes of condylar cartilage of temporomandibular joint(TMJ)and the expression changes of IL-1β、TNF-α、MMP-2、MMP-9、IGF-I and VEGF in the condylar cartilage of TMJ by establishing a chronic sleep deprivation model in rats.Methods:60 male Wistar rats(age of 8 week)were randomly divided into 3 groups,the experimental group(receiving chronic sleep deprivation),the control group and the recovery group.Using the modified multiple platforms method(MMPM)to build the chronic sleep deprivation of the experimental and recovery group of rats.Open field test was performed to evaluate the effect of sleep deprivation model of rats.At the end of the 1,2,3 and 4 week of sleep deprivation,5 rats in the experimental group and the control group were sacrificed respectively.The recovery group rats received 1 week of cage feeding after sleep deprivation,and then were sacrificed.Using the HE staining to observe the temporomandibular joint condyle’s morphological changes.And the immunohistochemical were performed to detect the changes of IL-1β、TNF-α、MMP-2、MMP-9、IGF-I and VEGF.Results:1.In the open field test,the horizontal and vertical scores of the experimental group and the recovery group at the end of chronic sleep deprivation were higher than those of the control group,with statistical significance(P<0.05),the positive expression intensity of the recovery group was lower than that of the experimental group at each time point(P<0.05);There was no significant difference in the horizontal and vertical scores between the recovery group and the control group after 1week sleep recovery(P>0.05)2.In experimental rats,with the increase of sleep deprivation time,condylar cartilage had the degenerative changes.HE dyeing observation found that after the chronic sleep deprivation,condylar cartilage in the surface layer fiber were split stripped,the proliferation lawyer and the cartilage cell lawyer’s boundaries became blurred.The subchondral bone grew deep into the cartilage.Compared with the control group,the recovery group had less cracks in the fibrous lawyer or some of the cracks were occupied by fibrous tissue with no cells grew inside.The number of mast cell were increased in some of the fibrochondral layer,and the boundary were cleared.3.Immunohistochemical results showed that the positive expression intensity of IL-1β,TNF-α,MMP-2 and MMP-9 in the experimental group at each time point was higher than that in the control group(P<0.05),the positive expression intensity in the recovery group at each time point was lower than that in the experimental group,which was statistically significant(P<0.05).The positive expression intensity of IGF-I and VEGF in the experimental group was higher than that in the control group,which was statistically significant(P<0.05).The expression intensity of IGF-I and VEGF decreased significantly in the 1 week,2 week and 3 week’s recovery group,which was statistically different from that in the experimental group(P<0.05).After 1 week of recovery,the expression intensity of IGF-I and VEGF decreased significantly in the 1,2 and 3 week groups,which was statistically different from that in the corresponding time group(P<0.05).The intensity of IGF-I and VEGF expression in the 4 week’s recovery group was not significantly different from that in the experiment group(P>0.05).Conclusions:1.The MMPM can effectively induce stress response and is a simple and effective way to establish chronic sleep deprivation model in male Wistar rat.2.Chronic sleep deprivation can cause inflammatory changes in condyle cartilage,and it is an appropriate choice to use chronic sleep deprivation modeling to study the pathological mechanism of TMJ OA.3.Chronic sleep deprivation can increase the expression of IL-1β and TNF-α in condyle cartilage and aggravate the osteoarthritis expression of condyle cartilage.4.Chronic sleep deprivation can increase the expression of MMP-2 and MMP-9 in condyle cartilage tissue,indicating that it may damage the cartilage matrix.5.Chronic sleep deprivation can lead to the increase of IGF-I expression in condyle cartilage tissue,which plays a role in protecting and promoting the reconstruction of condyle cartilage.6.Chronic sleep deprivation can increase the expression of VEGF in condyle cartilage tissue,aggravate the inflammatory manifestations of condyle cartilage,and cause the destruction of condyle cartilage.7.After chronic sleep deprivation was stopped,the expressions of IL-1β,TNF-α,MMP-2,MMP-9,IGF-I and VEGF in the condylar cartilage of rats were decreased after 1 week of recovery,and the condylar cartilage underwent restorative reconstruction.However,the condylar cartilage may need a longer recovery time after long-term chronic sleep deprivation. |
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