| Objective:The aim of the study was to observe the effects of the expression of p38MAPK signal transduction pathway in rats’ TMJ region with sleep deprivation(SD), whether it mediates the injury of the rats’TMJ.Methods:1.45Male wistar rats were randomly divided into large-platform control2d group、large-platform control4d group、large-platform control6d g roup、large-platform control8d group and SD2d group、SD4d group、SD6d group、 SD8d group and blank control group, each group has5rats. Rats in ea ch group in the corresponding same cage is kept. Before the experiment, the r ats were put into the corresponding model to adapt the environment with no st imulus. The SD group models were established by the modified multiple platfo rm method. The size of the sleep deprivation tank was110cm×70cm×40cm wit h the length、the width and the height respectively, the centre of which was pl aced15platforms with the diameter of6.3cm and the height of8cm. The dep rivation tank was filled with water, the platform is1cm higher than the water surface. The rats were free access to food and water, however, when entering sleep, the rats fell into the water due to the relaxation of skeletal muscle and wake up, causing sleep deprivation. The factors of the platform control group were consistent with the SD group except the diameter of the platform increa sed, the rats can carry out some activities and go to sleep. The blank control group was normally fed.2.After the success of modeling,2d group、4d group、6d group、8d group and blank group were respectively stained HE to observe the morphological changes of TMJ, SP immunohistochemical method was used to detect the expression of phosphorylated p38MAPK protein in rat TMJ zone (condylar), in the same time compared with the control group.3. Open field test:the rats were placed in the open field test, the level activity score and the vertical activity score were calculated in the5min.4. Statistical analysis:statistical analysis was performed using SPASS16.0software, P<0.05had significant difference.Results:1. General state observation:in the experiment, with the time of SD prolonged, the SD rats were panic, sensitive reaction, and fierce behavior performance; while the control group showed normal.2. HE staining observation:the condylar cartilage of the control group rat was divided into fibrous articular surface belt, multicellular belt, fibrocartilage zone and calcified cartilage zone from the shallower to the deeper in turn. The condyle and articular disc of the control group had no significant changes. SD2d group and4dgroup showed that the collagen fiber of rat temporomandibular joint condylar surface was edema、release, and articular disc appeared inflammatory reaction. The pathological changes of SD6d group were the more obvious, the articular disc appeared glassy degeneration, dissolution fracture, and the serious area cracked, condylar surface area was uneven, the surface of collagen fiber edema, release, and some bone cells disappeared, bone lacunae was empty, the changes of the SD8d group were similar to the SD6d.3. immunohistochemistry SP method:the phosthorylated MKK6is mainly expressed in the cytoplasm, positive staining was brown or yellow. The control group had rare phosphorylated MKK6positive cells, the positive cells in SD group were more than that in control group(p<0.05), dyed dark brown, and with the SD prolonged, the positive cells increased gradually and reached the peak at SD6d. Phosthorylated P38MAPK was mainly expressed in the nucleus, a few in the cytoplasm, and the positive staining was brown or yellow. The control group had rare phosphorylated p38MAPK positive cells, the positive cells in SD group were more than that in control group(p<0.05), dyed dark brown, and with the SD prolonged, the positive cells increased gradually and reached the peak at SD6d.4. The results of open field test:the black control group had no significant differences between the level and vertical activity compared to the big platform group (P>0.05). The level and vertical activity score in SD2d,SD4d,SD6d and SD8d group were higher than the platform group(p<0.05).Conclusion:The results of open field test showed that this sleep deprivation model is the ideal model of psychological stress, which can effectively simulate the human emotional and psychological changes caused by external factors. HE results showed that, compared with the control group, the temporomandibular joint structure in rats of SD group began to appear the obvious changes in the sleep deprivation4d,, the condylar surface was uneven, the surface of collagen fiber edema, release, the articular disc appeared inflammatory reaction, the damage is the most serious in the sleep deprivation6d, and appeared some adaptive reaction in the sleep deprivation8d. immunohistochemistry results showed that compared to the control group, phosphorylated MKK6and p38MAPK positive cells increased gradually with the SD prolonged and reached the peak at SD6d. The results of this study showed that sleep deprivation stress activates the rat temporomandibular joint area of the P38MAPK pathway, this pathway may mediate the damage process of TMJ region in rats. |
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