C-X-C motif chemokine ligand 1 and its receptor C-X-C motif chemokine receptor 2 in trigeminal ganglion contribute to nerve injury-induced orofacial mechanical allodynia.

BACKGROUND: Orofacial ectopic pain induced by trigeminal nerve injury is a serious complication of dental treatment. C-X-C motif chemokine ligand 1 (CXCL1) and its primary receptor C-X-C motif chemokine receptor 2 (CXCR2) contribute to the development and maintenance of neuropathic pain in the spinal nervous system, but their roles in trigeminal neuropathic sensation are still poorly understood. OBJECTIVES: This study aimed to investigate the exact role of CXCL1 and CXCR2 in the regulation of orofacial ectopic mechanical allodynia and their potential downstream mechanisms in the trigeminal ganglion (TG). METHODS: The head withdrawal threshold (HWT) of C57BL/6 mice was evaluated after inferior alveolar nerve (IAN) transection (IANX). Then, the distribution and expression of CXCL1 and CXCR2, and their potential downstream mechanisms in the TG were further measured using immunohistochemistry, real-time reverse transcription-quantitative polymerase chain reaction and Western blotting. Moreover, the effect of SB225002 (an inhibitor of CXCR2) on mechanical allodynia was examined. The data were analysed using the Student's t test and a analysis of variance (ANOVA). RESULTS: IANX triggered persistent (>21 days) mechanical allodynia and upregulation of CXCL1 and CXCR2 in the TG. In addition, exogenous CXCL1 also lowered the HWT, which was alleviated by CXCR2 and protein kinase C (PKC) antagonists (p < .05). In addition, IANX increased the phosphorylated PKC (p-PKC) levels and decreased the expression of voltage-gated potassium channels (Kv), and these effects were reversed by inhibition of CXCR2 (p < .05). CONCLUSION: Our results demonstrated that CXCR2 participated in orofacial ectopic mechanical allodynia via downregulation of Kv1.4 and Kv1.1 through the PKC signalling pathway. This mechanism may be a potential target in developing a treatment strategy for ectopic orofacial pain.

Acyl-CoA synthetases from Physcomitrella, rice and Arabidopsis: different substrate preferences but common regulation by MS188 in sporopollenin synthesis.

MAIN CONCLUSION: ACOS5, OsACOS12 and PpACOS6 are all capable of fatty acyl-CoA synthetase activity but exhibit different substrate preferences. The transcriptional regulation of ACOS for sporopollenin synthesis appears to have been conserved in Physcomitrella, rice and Arabidopsis during evolution. Sporopollenin is the major constituent of spore and pollen exines. In Arabidopsis, acyl-CoA synthetase 5 (ACOS5) is an essential enzyme for sporopollenin synthesis, and its orthologues are PpACOS6 from the moss Physcomitrella and OsACOS12 from monocot rice. However, knowledge regarding the evolutionary conservation and divergence of the ACOS gene in sporopollenin synthesis remains limited. In this study, we analysed the function and regulation of PpACOS6 and OsACOS12. A complementation test showed that OsACOS12 driven by the ACOS5 promoter could partially restore the male fertility of the acos5 mutant in Arabidopsis, while PpACOS6 did not rescue the acos5 phenotype. ACOS5, PpACOS6 and OsACOS12 all complemented the acyl-CoA synthetase-deficient yeast strain (YB525) phenotype, although they exhibited different substrate preferences. To understand the conservation of sporopollenin synthesis regulation, we constructed two constructs with ACOS5 driven by the OsACOS12 or PpACOS6 promoter. Both constructs could restore the fertility of acos5 plants. The MYB transcription factor MS188 from Arabidopsis directly regulates ACOS5. We found that MS188 could also bind the promoters of OsACOS12 and PpACOS6 and activate the genes driven by the promoters, suggesting that the transcriptional regulation of these genes was similar to that of ACOS5. These results show that the ACOS gene promoter region from Physcomitrella, rice and Arabidopsis has been functionally conserved during evolution, while the chain lengths of fatty acid-derived monomers of sporopollenin vary in different plant species.

Effects of Low-Level Laser Therapy on Osseous Defects Distal to Mandibular Second Molar after Extraction of Impacted Third Molar.

Objective: To evaluate the efficiency of low-level laser therapy on the distal osseous defects of the mandibular second molar (M2) after the adjacent impacted third molar (M3) extraction. Methods: A total of 59 clinic cases were screened out, whose M3 were impacted and the distal alveolar bone of M2 had been destroyed horizontally. They were randomly divided into 2 groups based on whether they would have laser irradiation or not after M3 extraction. Then, postoperative complications of the 2 groups were compared. The alveolar bone level distal to M2 was established before and 3 to 6 months after M3 extraction by radiographic evaluation, which was compared between two groups. Results: The incidence of severe pain and mouth-opening limitation was significantly lower in the LLLT group than that in the control group. The amount of bone formation in the LLLT group was higher than that in the control group 3 months after the operation, and the difference was statistically significant. But the difference was not statistically significant 6 months after surgery. Conclusion: LLLT may alleviate postoperative complications and improve early osteogenesis. It is a viable option for use in the treatment of osseous defects distal to mandibular second molars following extraction of impacted third molars.

[Anti-aging effect of dental pulp stem cells on skin fibroblasts].

PURPOSE: To investigate the effect of dental pulp stem cells on the senescence and proliferation of skin fibroblasts, and to explore the underlying mechanism. METHODS: Dental pulp stem cells (DPSCs) were extracted from human dental pulp and then skin fibroblasts were co-cultured with DPSCs. The experiment was divided into three groups: control group (single skin fibroblasts culture), conditioned medium group (skin fibroblasts cultured with DPSCs conditioned medium), direct co-culture group (skin fibroblast cultured with DPSCs in Transwell chambers). After co-culture, the senescence of fibroblasts was detected by SA-ß-gal staining.CCK-8 method was used to detect the activity of fibroblasts. The cell cycle of fibroblasts was analyzed by flow cytometry. mRNA and protein expression levels of senescence related proteins p21, p53 and pRb were detected by RT-PCR and Western blot. SPSS 13.0 software package was used for statistical analysis of the experimental data. RESULTS: Compared with the control group, skin fibroblasts in the latter two groups showed decreased expression of SA-ß-gal and increased proliferation ability. Cell cycle test showed that skin fibroblasts decreased in G1 phase and increased in S and G2 phase in conditioned medium group and direct co-culture group. RT-PCR and Western blot results showed decreased expression levels of p53, p21 mRNA and protein, and increased levels of pRb in conditioned medium group and direct co-culture group. CONCLUSIONS: Dental pulp stem cells and their conditioned medium have anti-aging effect on skin fibroblast. The results of this study provide theoretical basis for the clinical application of dental pulp stem cells in anti-aging.

[The curative effect of rhubarb extract on severe periodontitis in patients with diabetes mellitus].

PURPOSE: To observe the curative effect of rhubarb extract on severe periodontitis in patients with diabetes mellitus. METHODS: Fifty patients with severe periodontitis and diabetes mellitus were randomly divided into 2 groups. The patients in the control group were treated with scaling and root planning(SRP); while patients in the experimental group were treated with SRP followed by topical use of rhubarb extract. Periodontal index probing pocket depth (PD), clinical attachment level (CAL) and bleeding on probing (BOP) were examined before periodontal treatment，6 weeks and 12 weeks after treatment. SPSS 20.0 software package was used for statistical analysis. RESULTS: Significant improvement in periodontal condition was noted in both groups after treatment, and the degree of improvement was greater in the experimental group than in the control group. No adverse event during the entire study was found. CONCLUSIONS: Topical application of rhubarb extract for the treatment of severe periodontitis with diabetes has good clinical efficacy.

[Effects of free dental filling interventions on early childhood primary tooth caries in Shanghai Jiading district].

PURPOSE: To provide scientific basis for the establishment of oral health care polices in Jiading, and to evaluate the effectiveness of a free dental filling intervention conducted for childen in Jiading district. METHODS: Nine hundred and eighteen children of 3-5 year old from two kindergartens with similarities in living environments and economic conditions were enrolled in this study. Children in the intervention group received both oral health examination and free filling of shallow and moderate caries once a year for 3 years, while children in the control group received only oral health examination once a year. The data were analyzed with SPSS 20.0 software package for Chi-square test. RESULTS: Total caries prevalence，mean dft and CSI of the two groups had no significant difference in the first year. There was significant difference between the two groups in caries prevalence, mean dft and CSI (which were 43.90%, 2.86 and 7.34, respectively) after 3 years of the interventions. CONCLUSIONS: Free dental filling intervention programme is effective in early prevention and control of caries.

[Evaluation of the application of tooth/JIAD(KOM) implant-supported restoration].

PURPOSE: To investigate the effect of tooth/implant -supported restoration. METHODS: Twenty patients were divided into 2 groups randomly. In the group A, ten patients received tooth/implant supported restoration and in the group B, ten patients received implant only restoration. The absorption rate of bone tissue, the change of soft tissue, the survival rate of the implant and the degree of patients' satisfaction were collected during the follow-up three years after treatment. The data was analyzed by SPSS 14.0 software package for Student's t test. RESULTS: The survival rate of the implants in the 2 groups was 100%. The bone tissue absorption rate in the group A was (1.0±0.28)mm and (1.0±0.23)mm in the group B, the difference was not significant(P>0.05). No significant difference was found in bone absorption, change of soft tissue and degree of patients' satisfaction. CONCLUSION: Short-term success can be achieved to use tooth/implant-supported restoration for implant without any physical mobility.