The expression of SP and CGRP in the temporomandibular joints of the rats undergone emotional stress

Abstract

Objective To observe the substance P(SP) and calcitonin gene-related peptide(CGRP) expressions in the temporomandibular joints(TM J) of the rats undergone emotional stress and explore the relationship between emotional stress and temporomandibular joint disorder(TMD). Methods Ninety SD rats were averagely randomly divided into emotional stress ( ES ) group( n = 30 ), electric foot-shocked (FS) group ( n = 30 ) and control (CON) group( n = 30). The emotional stress was induced by communication box. The TMJ tissues in ES and CON groups were removed after 1, 3 and 5 weeks of emotional stress for scanning electron microscope ( SEM ) test and immunohistochemistry test. The SP and CGRP expressions were examined with SABC immunohistochemistry and then analyzed by image analysis system. Results The expressions of SP and CGRP had significant difference after 1 ,3 and 5 weeks emotional stress ( SP: 124.5 ± 16.9,185.6 ± 1.8 and 193.5 ± 3.5, respectively; CGRP: 185.9 ±5.3, 112.5 ±5.2 and 174.3 ±5.3 ,respectively) (P＜0. 05 ). The SEM results showed that there was a series of structural change on the condylar surface after emotional stress. Conclusion The SP and CGRP energy nerve fibers take part in the TMJ pathological process undergone emotional stress. Key words: Substance P; Calcitonin gene related peptide; Temporomandibular joint; Emotional stress