[Effects of Morinda officinalis polysaccharides on FN and FN-EDA of periodontal ligament fibroblasts in inflammatory microenvironment].

PURPOSE: To investigate the effect of Morinda officinalis polysaccharides(MOP) on the expression of fibronectin(FN) and fibronectin containing extra domain A(FN-EDA) in inflammatory periodontal ligament fibroblasts. METHODS: Thirty six rats were randomly divided into a control group(n=12) and a model group (n=24). The model group used orthodontic wire ligation to establish periodontitis. After three weeks, 6 rats from each group were selected and confirmed by Micro-CT to complete the modeling. The remaining rats in the model group were randomly divided into periodontitis group, normal saline(NS) group, and MOP group. In the MOP group, MOP (200 mg/kg for 3 d, 50 µL for 4 weeks) was injected into the palatal side of the left maxillary first molar of the rats. In the NS group, same volume of NS was injected, and no treatment was performed in the periodontitis group. The left maxillary tissue of rats were taken and the pathological changes of periodontal tissue were observed by H-E staining. The expression of FN and FN-EDA was detected by immunohistochemistry. Periodontal ligament fibroblasts were cultured in vitro, the effect of MOP on cell activity detected by CCK-8. The fourth generation cells were divided into control group, inflammation group (10 mg/mL lipopolysaccharide), and experimental group (12.5 µg/mL MOP, 12.5 µg/mL MOP+10 mg/mL lipopolysaccharide). The expression of FN and FN-EDA was detected by qRT-PCR and Western blot. The data were statistically analyzed using Prism 8.0 software package. RESULTS: In vivo experiments, the expression of FN-EDA in the MOP group was significantly lower than that in the periodontitis group and NS group(P＜0.05), and the infiltration of inflammatory cells was reduced. However, there was no significant difference in the expression of FN in each group. In vitro experiments, compared with the control group, the expression of FN-EDA mRNA and protein in the inflammation group was significantly increased(P＜0.000 1). MOP significantly reduced the expression of FN-EDA in inflammatory cells, but had no significant effect on FN expression. CONCLUSIONS: With increased expression of FN-EDA in inflammatory periodontal ligament tissues and cells, MOP may play a role in inhibiting inflammation by down-regulating FN-EDA.

Morinda officinalis polysaccharides inhibit the expression and activity of NOD-like receptor thermal protein domain associated protein 3 in inflammatory periodontal ligament cells by upregulating silent information regulator sirtuin 1.

OBJECTIVES: This study aims to investigate the effect of morinda officinalis polysaccharides (MOP) in inflammatory microenvironment on the expression of silent information regulator sirtuin 1 (SIRT1) and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) in periodontal ligament cells. METHODS: Thirty rats were randomly divided into control group (n=6) and model group (n=24). The model group used orthodontic wire ligation to establish periodontitis, and six rats from each group were killed after 3 weeks. The successful modeling was confirmed by Micro-CT. The remaining rats in the model group were randomly divided into natural recovery group, normal saline (NS) group, and MOP group. In the MOP group, MOP [200 mg/(kg·3d), 50 µL for 4 weeks] was injected into the palatal side of the left maxillary first molar of the rats, while the NS group was injected with equal volume of NS. The natural recovery group did not undergo any treatment. The left maxilla tissues of the rats were collected, and pathological changes in perio-dontal ligament cells were observed by hematoxylin-eosin (HE) staining. The expression of SIRT1 and NLRP3 was detected by immunohistochemistry. Cultivate periodontal ligament fibroblasts in vitro and detect the effect of MOP on cell activity using CCK-8. The 4th generation cells were divided into control group, inflammation group (10 µg/mL lipopolysaccharide), and experimental group (5 µmol/L MOP, 5 µmol/L MOP+10 µg/mL lipopolysaccharide). The expression of SIRT1 and NLRP3 was detected by quantitative realtime polymerase chain reaction (qRT-PCR) and Western blot analyses. The acetylation of NLRP3 and the contents of interleukin (IL)-1ß and IL-18 were detected by immunoprecipitation and enzyme-linked immunosorbent assay, respectively. Statistical analysis of data was conducted using Prism 9.0 software. RESULTS: In the vivo experiments, the expression of NLRP3 and SIRT1 in the MOP group decreased significantly compared with that in the natural recovery group and NS group, while the expression of SIRT1 increased (P<0.05) and inflammatory cell infiltration decreased. In the in vitro experiments, the expression of NLRP3 mRNA and protein in the inflammation group increased (P<0.05), while the expression of SIRT1 significantly decreased (P<0.01); MOP upregulated the expression of SIRT1 in inflammatory cells (P<0.05), reduced the expression of NLRP3 and its acetylation level significantly (P<0.05), suppressed the content of IL-1ß and IL-18 in the supernatant (P<0.01). CONCLUSIONS: The SIRT1 expression decreased, and that of NLRP3 expression increased in inflammatory periodontal ligament cells. MOP intervention promoted SIRT1 expression, resulting in the inhibition of NLRP3. Meanwhile, the acetylation level of NLRP3 reduced through deacetylation, leading to the decreased activity of NLRP3. Thus, MOP acted as inflammatory suppressor.