OBJECTIVETo investigate the expression of the Toll-like receptor-4 (TLR-4) in temporo-mandibular joint synovitis in rats, and to discuss the correlation between the expression of TLR-4 and the synovitis.

METHODSSixty male wistar rats were randomly divided into five groups, 12 each. Group A was the control group in which the rats were given normal diet.In Group B, the rats' bilateral masseter muscles were cut off (masseter resection group). In Group C, An cast metal crown were bonded on the mandibular right first molar of each rat (occlusal interference group). In Group D, occlusal pad were bonded on maxillary molars of each rat (occlusal dimension increase group). In Group E, rats' bilateral masseter muscles were re-sected and occlusal pads were bonded on their maxillary molars (masseter resection and occlusal dimension increase group). Pathological changes of synovium were observed using hematoxylin and eosin (HE) stains and pathology scores were evaluated. The expression of TLR- 4 were determined by immunohistochemical stains, and the expression of TLR-4 mRNA were determined by real-time PCR. The correlation between the expression of TLR-4, TLR-4 mRNA and the pathological score were analyzed using Spearman analysis.

RESULTSThe pathological scores of Group A-E were 0.5 ± 0.5, 2.5 ± 1.0, 2.7 ± 1.0, 3.0 ± 0.9, 5.3 ± 1.2 respectively. The expression of TLR-4 were (3.2 ± 1.5)%, (16.± 2.6)%, (15.8 ± 2.1)%, (17.5 ± 2.4)%, (38.2 ± 4.4) %. The expression of TLR-4 mRNA were 1.07 ± 0.09, 2.12 ± 0.33, 2.07 ± 0.29, 2.17 ± 0.34, 4.53 ± 0.46. Compared with group A, groups B- E showed significant higher pathology score (P < 0.05) and increased expression of both TLR-4 (P < 0.05) and TLR-4 mRNA (P < 0.05). An significant positive correlation was found between the expression of TLR- 4 and the pathology score (r = 0.785, P < 0.05), and between the expression of TLR- 4 mRNA and the pathology score (r = 0.720, P < 0.05).

CONCLUSIONSTLR-4 may be closely associated with the development of the synovitis of TMJ of rats.

Animals ; Male ; Masseter Muscle ; RNA, Messenger ; Rats ; Rats, Wistar ; Synovial Membrane ; Synovitis ; metabolism ; Temporomandibular Joint ; metabolism ; Toll-Like Receptor 4 ; biosynthesis

Direct acid hydrolysis of Dioscorea zingiberensis rhizomes for preparation of diosgenin is wildly used in the traditional industry， which uses a large amount of inorganic acid catalysts， with high wastewater discharge and serious environmental pollution. Therefore， exploring clean and efficient preparation methods and processes has become an inevitable choice to realize the sustainable development of industrial production of diosgenin. Herein， the author reviewed and analyzed the research progress and problems of enzymatic hydrolysis， microbial transformation and modified acid hydrolysis in the preparation of diosgenin from D. zingiberensis rhizomes during the last ten years， and their application prospects are analyzed. Enzymatic hydrolysis has mild reaction conditions， but the yield of diosgenin is low， the economic cost is high， and the purification process of active enzyme is complicated. Microorganism shows specific activity to the substrate and high efficiency for diosgenin production， and microbial transformation is clean and environmentally friendly， but microbial transformation is time-consuming and the metabolic intermediates are complicated. For the modified acid hydrolysis， two-phase acid hydrolysis can reduce the amount of acid catalyst， and sulfonic acid-functionalized ionic liquid displays good recyclable performance by replacing the traditional inorganic acid， however， the wastewater discharge should still be considered. Solid acid catalysts are non-corrosive and easy to be recycled， but the need to use ethanol as the reaction solvent has certain safety hazards， and the catalyst preparation process is cumbersome. In conclusion， exploring clean and efficient conversion methods is an important research trend for preparation of diosgenin from D. zingiberensis rhizomes. For the enzymatic hydrolysis， the key glycoside hydrolases in the bioconversion process should be explored in depth， the conversion pathway of enzymatic saponins and enzyme specificity should be fully elucidated， and efforts should be made to improve the efficiency of enzymatic hydrolysis. For the microbial transformation， we should accelerate its industrial application process based on selecting and breeding efficient transformation strains， and optimizing stable transformation systems and processes， and in-depth investigation of the mechanism of microbial transformation， fully elucidating the specific key hydrolases and its catalytic properties， and striving to improve the efficiency of microbial transformation. For the modified acid hydrolysis， novel acid catalytic system with simple structure， stable performance and good biodegradability should be explored and applied， which can effectively solve the problems of environmental pollution and production safety.