Changes of the ultrastructures of temporomandibular joint after removal of emotional stress factors in rats

Abstract

To examine the changes of the ultrastructures of temporomandibular joint after removal of the emotional stress factors in rats. Thirty-two 12-week-old male Wistar rats were divided into two groups randomly, experimental group and control group. Each group was divided into two subgroups according to execution time, 9-week subgroup and 12-week subgroup with eight rats in each subgroup. Chronic unpredictable stress animal model were firstly established in experimental group in the first 6 weeks, then all the stimulation factors removed and breed normally. After 9 weeks, rats in 9-week subgroup were killed. After 12 weeks, rats in 12-week subgroup were killed. All condyles and articular discs were dissected and observed by scanning electron microscope. There was some recovery in condyles and articular discs in experimental group under scanning electron microscope. The gelatum on the surface of condyles increased, collagen fibrils became regular and deep layer collagen fibrils less exposed. There were no such obvious changes on the surface of condyles and articular discs in control group. The ultrastructure injures of temporomandibular joint in rats induced by emotional stress could be reversed if the stress factors were removed.