| Objective:To observe the expressions of matrix metallopeptidase-3(MMP-3)、tissue inhibitor of metalloproteinase-3(TIMP-3)、vascular endothelial growth factor (VEGF)and transforming growth factor-β1(TGF-β1) in condylar chondrocytes of rats under psychological stress. Methods:Forty-eight adult male Wistar rats were randomly divided into the experimental group(36rats) and the control group(12rats). The rats were divided into three groups (12in each) according to the duration of psychological stress:3weeks,6weeks, and6weeks of recovery. The other group of12rats was used as the control. Thirty-six Wister male adult rats in the experimental group were subjected to the following stimulating factors, such as electroshock, deprivation sleep, keeping stillness, climate change and food tempting to achieve psychological stress. Then, the experimental group rats were executed at3weeks after stimulation (3weeks stimulation group),6weeks after stimulation (6weeks stimulation group) and6weeks normal feeding after6week stimulation (recovery group),12rats were sacrificed at each time point. The12rats in the control group were executed at12weeks. The temporomandibular joint specimens were taken to produce slices. Immunohistochemical staining using Streptomyces avidin-peroxidase coupled method (S-P method). Result:The positive expression rate of VEGF in the recovery group was significantly higher than that in the3-week and recovery group (P<0.005). The positive expression rate of TGF-β1and MMP-3in the6-week group was significantly higher than that in the control group (P<0.008). The positive expression rate of TIMP-3in the recovery group was significantly higher than that in the control group (.P=0.007), while the difference was not significant for other between-group comparisons(P>0.05). Conclusion:Purely psychological stress can increase the expression of MMP-3and TGF-β1in condylar cartilage. With the prolongation the stress time, it can also increase the expression of TIMP-3and VEGF. It may be one of the mechanisms that psychological stress lead to condylar cartilage of extracellular matrixc damaging and repairring. |
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