Psychological stress alters the ultrastructure and increases IL-1β and TNF-α in mandibular condylar cartilage

Psychological factors can be correlated with temporomandibular disorders (TMDs), but the mechanisms are unknown. In the present study, we examined the microstructural changes and expression of proinflammatory cytokines in mandibular condylar cartilage of the temporomandibular joint (TMJ) in a psychological stress animal model. Male Sprague-Dawley rats (8 weeks old, 210 ± 10 g) were randomly divided into 3 groups: psychological stress (PS, N = 48), foot shock (FS, N = 24), and control (N = 48). After inducing psychological stress using a communication box with the FS rats for 1, 3, or 5 weeks, PS rats were sacrificed and compared to their matched control littermates, which received no stress and were killed at the same times as the PS rats. Body and adrenal gland weight were measured and corticosterone and adrenocorticotropic hormone levels were determined by radioimmunoassay. After hematoxylin-eosin staining for histological observation, the ultrastructure of the TMJ was examined by scanning electron microscopy. Transcription and protein levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were evaluated by ELISA and semi-quantitative RT-PCR. The PS group showed a significantly higher adrenal gland weight after 3 weeks of stress and higher hormone levels at weeks 1, 3, and 5. Histopathological changes and thinning cartilage were apparent at weeks 3 and 5. In the PS group, TNF-α increased at 1, 3, and 5 weeks and IL-1β increased significantly after 1 and 3 weeks of stress, and then decreased to normal levels by 5 weeks. Psychological stress increased plasma hormone levels and RT-PCR indicated increased IL-1β and TNF-α expression in the TMJ in a time-dependent manner. These results suggest that cytokine up-regulation was accompanied by stress-induced cartilage degeneration in the mandibular condyle. The proinflammatory cytokines play a potential role in initiating the cartilage destruction that eventually leads to the TMDs.

Construction of eukaryotic expression vector of HCV CTL epitopes and establishment of stable transfected CHO cell line / 临床肝胆病杂志

@#Objective To construct eukaryotic expression vector of hepatitis C virus (HCV) cytotoxic T-lymphocyte (CTL) epitopes, and to establish stable transfected CHO cell-lines.Methods The HCV CTL epitopes of different genotypes and the mouse H2 complex were predicted by bioinformatics, then synthesized and inserted into eukaryotic expression vector pEGFP-N3.The recombinant vector was transfected into CHO cells by lipofectamine 2000.After screening with G418, stably transfected CHO cell line was established.The expression of HCV multi-epitopes was identified by RT-PCR and western-blot and immunofluorescence.Results The eukaryotic expression vector was constructed successfully.The stable transfected CHO cell line was established.Conclusion The establishment of stable transfected CHO cell line and the expression of the target gene provide solid foundation for further experimental studies.