OBJECTIVETo investigate the effects of non-surgical periodontal therapy on serum inflammatory factors and metabolism levels in obese rats with experimental periodontitis.

METHODSSixteen obese rats with experimental periodontitis were randomly divided into treatment group and control group with non-surgical periodontal therapy and no treatment, respectively. Oral glucose tolerance test was performed before treatment and 2 weeks after the treatment. All the rats were sacrificed 2 weeks after treatment and the orbital vein blood was taken to detect fasting blood glucose, fasting insulin, and serum level of C-reactive protein (CRP). Results Two weeks after periodontal treatment, fasting blood glucose (t=2.445, P=0.034) and beta cell function index (t=-2.543, P=0.027) were significantly lower in the treatment group than in the control group. Compared with those in the control group, CRP level (t=2.388, P=0.028) and the area under the curve in the oral glucose tolerance test (t=12.053, P=0.000) decreased significantly in the treatment group.

CONCLUSIONNon-surgical periodontal treatment can reduce serum CRP level and improve glucose metabolism in obese rats.

OBJECTIVETo investigate the effect of periodontal therapy in controlling periodontitis and on insulin resistance and lipid metabolism in obese rats with periodontitis.

METHODSSprague-Dawley rats were randomized into normal group (group C), obese group (group O), periodontitis combined with obesity group (group P) and periodontal treatment group (group T). The obese rats in groups P and T were subjected to ligation of the maxillary second molar with silk thread to induce experimental periodontitis, and the rats in group T received periodontal therapy after the ligation. All the rats were sacrificed at the age of 24 weeks for measurement of blood lipids, insulin and blood glucose levels, and insulin resistance index (HOMA-IR) was calculated. The expressions of insulin receptor substrate-1 (IRS-1) and IRS-2 in the liver tissues were detected using real-time quantitative polymerase chain reaction (RT-PCR).

RESULTSCompared with the obese rats in group O, the rats in group P showed significantly higher HOMA-IR and LDL-C and lower expressions of IRS-1 and IRS-2 mRNA expression and HDL-C level (P<0.05). Compared with those in group P, the mRNA expressions of IRS-1 and IRS-2 and HDL-C level were significantly increased and LDL-C level, TC level and HOMA-IR were all decreased in group T (P<0.05), but the level of TG was comparable between the two groups. Pathological examination revealed lessened inflammatory cell infiltration and tissue destruction in the upper jaw of the rats in group T; the rats in group P presented with the most obvious upper jaw destruction and steatosis and inflammatory cell infiltration in the liver.

CONCLUSIONPeriodontal inflammation can downregulate the expression of IRS-1 and IRS-2 and increase insulin resistance and dyslipidemia in obese rats. Periodontal therapy produces a beneficial effect in improving insulin resistance and reducing dyslipidemia in obese rats.

A two-dimensional liquid chromatography method was developed for the analysis of rice leaves proteomics based on the coupling of hydrophilic interaction liquid chromatography-reversed-phase liquid chromatography with online tandem mass spectrometry. The influence of pH value of chromatographic mobile phase on the orthogonality of the hydrophilic interaction-reversed-phase two-dimensional liquid chromatography was evaluated by the changes of standard peptide retention. The results indicated that the better orthogonality (R2=0.34113) was achieved from the system with hydrophilic interaction columns(pH 9.3) in the first and C18columns(pH 3.3) in the second LC dimension. Coupled with multiple fraction concatenation strategy,the orthogonality of two-dimensional liquid chromatography was further evaluated in the analysis of complex rice leaf proteins. The results showed that more than 50% of the total peptides were identified less than two times, and the peptides obtained from first-dimension were well distributed across the elution window,indicating that the method showed significant orthogonality in the identification of complex rice leaf proteins. Based on the proteome discoverer software,207345 peptides belonged to 2930 protein clusters were identified.

It is an urgent demand worldwide to control the coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The 3-chymotrypsin-like protease (3CL^pro) and papain-like protease (PL^pro) are key targets to discover SARS-CoV-2 inhibitors. After screening 12 Chinese herbal medicines and 125 compounds from licorice, we found that a popular natural product schaftoside inhibited 3CL^pro and PL^pro with IC₅₀ values of 1.73 ± 0.22 and 3.91 ± 0.19 μmol/L, respectively, and inhibited SARS-CoV-2 virus in Vero E6 cells with EC₅₀ of 11.83 ± 3.23 μmol/L. Hydrogen-deuterium exchange mass spectrometry analysis, quantum mechanics/molecular mechanics calculations, together with site-directed mutagenesis indicated the antiviral activities of schaftoside were related with non-covalent interactions with H41, G143 and R188 of 3CL^pro, and K157, E167 and A246 of PL^pro. Moreover, proteomics analysis and cytokine assay revealed that schaftoside also regulated immune response and inflammation of the host cells. The anti-inflammatory activities of schaftoside were confirmed on lipopolysaccharide-induced acute lung injury mice. Schaftoside showed good safety and pharmacokinetic property, and could be a promising drug candidate for the prevention and treatment of COVID-19.