Polarization of macrophages in the trigeminal ganglion of rats with pulpitis.

BACKGROUND: Dental pulp tissues are rich in pain-related afferent nerve fibers, which originate from primary sensory neurons in the trigeminal ganglion (TG). The mechanisms of central nervous system (CNS) underlying ectopic pain following peripheral inflammation have been reported that the macrophages as inflammatory and immunologic mediators in the TG play an important role in the process of pulpitis and hyperalgesia. OBJECTIVE(S): To observe the polarization response and dynamic distribution of macrophages in the TG during the development of dental pulp inflammation. METHODS: A rat model of pulpitis was established using complete Freund's adjuvant (CFA). Hematoxylin-eosin (HE), immunohistochemistry (IHC), immunofluorescence (IF), toluidine blue (TB) staining, and RT-qPCR were performed to observe the expression of macrophage-related factors in the TG. RESULTS: The results of IHC staining showed that M2 macrophages labeled with CD206 were observed in the TG of both the control and CFA groups. The statistical analysis indicated that the number of CD206-positive macrophages in the TG increased significantly at 24 h after CFA-induced pulpitis, reached a peak at 2 weeks, and then returned to the normal level after 6 weeks. The ratio of M2/M1 in the CFA groups was significantly lower than that in the control group from 24 to 72 h, and this pattern was reversed at 2 weeks after CFA-induced pulpitis; then, the ratio increased significantly and was maintained at a high level for 4 weeks. RT-qPCR results showed that the expression of IL-10 in the TG increased significantly from 1 to 4 weeks after CFA-induced pulpitis. CONCLUSION: The trend of M2 macrophages was opposite to that of M1 macrophages in the TG during the process of pulpitis induced by CFA, which is consistent with the expression of macrophage-related cytokines. Macrophage polarization in the TG may participate in the neuroinflammation response induced by dental pulpitis.

JAK2-STAT3 signaling pathway is involved in rat periapical lesions induced by Enterococcus faecalis.

OBJECTIVES: This study aimed to investigate the role of JAK2-STAT3 (Janus kinase 2/signal transducer and activator of transcription 3) in periapical disease caused by Enterococcus faecalis, as well as the correlation between lipoteichoic acid (LTA) in E. faecalis and the activity of the JAK2-STAT3 signaling pathway and osteoclast formation. MATERIALS AND METHODS: A rat model of periapical periodontitis induced by E. faecalis was established. Periapical bone resorption was confirmed by HE staining. The expression of JAK2, p-JAK2, STAT3, and p-STAT3 was assessed with immunohistochemical staining. Osteoclasts were observed through enzyme histochemical staining. LTA acted on mouse osteoclast precursor cells (RAW264.7 cells); a JAK2 inhibitor (AG490) was used to inhibit the JAK2-STAT3 pathway in RAW264.7 cells. The expression of proteins in the JAK2-STAT3 pathway and TRAP (tartrate resistant acid phosphatase) in RAW264.7 cells was also detected. RESULTS: Rat periapical periodontitis was successfully established and bone resorption peaked at day 21. The expression of critical components in the JAK2-STAT3 pathway increased with the progression of inflammation. LTA promoted the differentiation of RAW264.7 cells into osteoclasts. NFATc1 was highly expressed and was inhibited by AG490. CONCLUSIONS: JAK2-STAT3 signaling pathway plays an important role in the process of periapical bone resorption and osteoclastogenesis.

Utilizing surfactants to control the sorption, desorption, and biodegradation of phenanthrene in soil-water system.

An integrative technology including the surfactant enhanced sorption and subsequent desorption and biodegradation of phenanthrene in the soil-water system was introduced and tested. For slightly contaminated agricultural soils, cationic-nonionic mixed surfactant-enhanced sorption of organic contaminants onto soils could reduce their transfer to plants, therefore safe-guarding agricultural production. After planting, residual surfactants combined with added nonionic surfactant could also promote the desorption and biodegradation of residual phenanthrene, thus providing a cost-effective pollution remediation technology. Our results showed that the cationic-nonionic mixed surfactants dodecylpyridinium bromide (DDPB) and Triton X-100 (TX100) significantly enhanced soil retention of phenanthrene. The maximum sorption coefficient Kd of phenanthrene for contaminated soils treated by mixed surfactants was about 24.5 times that of soils without surfactant (Kd) and higher than the combined effects of DDPB and TX100 individually, which was about 16.7 and 1.5 times Kd, respectively. On the other hand, TX100 could effectively remove phenanthrene from contaminated soils treated by mixed surfactants, improving the bioavailability of organic pollutants. The desorption rates of phenanthrene from these treated soils were greater than 85% with TX100 concentration above 2000 mg/L and approached 100% with increasing TX100 concentration. The biodegradation rates of phenanthrene in the presence of surfactants reached over 95% in 30 days. The mixed surfactants promoted the biodegradation of phenanthrene to some extent in 10-22 days, and had no obvious impact on phenanthrene biodegradation at the end of the experiment. Results obtained from this study provide some insight for the production of safe agricultural products and a remediation scheme for soils slightly contaminated with organic pollutants.

The potential effect of Bruton's tyrosine kinase in refractory periapical periodontitis.

To determine the expression of Bruton's tyrosine kinase (BTK) in refractory periapical periodontitis and analyze the relationship between BTK and bone resorption in refractory periapical periodontitis. The mechanism of bone resorption is also discussed. The OneArray Plus expression microarray was used to screen for genes related to refractory periapical periodontitis. Real-time PCR was used to detect the expression of BTK in refractory periapical periodontitis tissues. A model of periapical periodontitis was established by sealing E.faecalis into the pulp of rats. To establish a model of E.faecalis LTA infection of osteoclasts, the relationship between BTK and bone destruction during refractory periapical periodontitis was analyzed. OneArray Plus expression microarray results showed that we found that the expression of 1787 genes in the two samples was different. After validating these samples, we found that BTK was closely related to refractory periapical periodontitis. The results showed that the expression of BTK in refractory periapical periodontitis tissues was higher than that in normal tissues. Immunohistochemistry, enzyme histochemistry and real-time PCR showed that the BTK expression curve in the experimental model resembled a reverse V shape from week 1 to week 4. Osteoclasts were cultured in vitro and treated with E. faecalis LTA. The expression of BTK in the E. faecalis model was greater than that in the control group. BTK played an important role in the progression of refractory periapical periodontitis.

Enterococcus faecalis Lipoteichoic Acid-induced NLRP3 Inflammasome via the Activation of the Nuclear Factor Kappa B Pathway.

INTRODUCTION: We wished to examine the effects of the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome on periapical periodontitis induced by Enterococcus faecalis and to investigate the molecular mechanisms of lipoteichoic acid (LTA) derived from E. faecalis on the expression of the NLRP3 inflammasome. METHODS: A model of periapical periodontitis by sealing E. faecalis into the pulp chambers of rats was established. We then examined the relationship between the expression, location, distribution, and concentration of NLRP3, caspase-1, and interleukin 1ß with the inflammatory progression by immunohistochemistry and undertook correlation analyses. RAW264.7 cells were cultured in the absence or presence of LTA together with or without nuclear factor kappa B (NF-κB) inhibitor BAY 11-7082; NLRP3 inflammasome expression was measured by Western blotting, the enzyme-linked immunosorbent assay, and real-time quantitative polymerase chain reaction. An immunofluorescence study was conducted to further detect whether NF-κB can be completely inhibited by BAY 11-7082 or activated by LTA. RESULTS: An animal model of periapical periodontitis was established successfully. Expression of NLRP3, caspase-1, and interleukin 1ß protein was observed in the inflamed area. The expression of these 3 proteins had a significant positive correlation (P < .05). Overall, our results showed that, compared with the negative control group, LTA could directly activate expression of messenger RNA and protein of the NLRP3 inflammasome (P < .05), whereas BAY 11-7082 inhibited it (P < .05). CONCLUSIONS: Our results suggested that LTA can act as a directly stimulating factor associated with expression of the NLRP3 inflammasome during periapical periodontitis, which is mainly linked with the NF-κB signaling activation pathway.