18β-Glycyrrhetinic Acid Monoglucuronide (GAMG) Alleviates Single-Walled Carbon Nanotubes (SWCNT) -Induced Lung Inflammation And Fibrosis In Mice Through PI3K/AKT/Nf-κB Signaling Pathway

BackgroundCarbon nanotubes(CNT)have become far and wide used in a number of technical and merchant applications as a result of substantial advances in nanotechnology,therein single-walled carbon nanotubes(SWCNT)are one of the most promising nanoparticles.Inhaling CNT has been linked to a variety of health problems,including lung fibrosis.Glycyrrhetinic acid 3-O-mono-β-D-glucuronide(GAMG),a natural sweetener,has antiinflammatory and antioxidant capacities.The purpose of this study was to evaluate the potential for GAMG to alleviate SWCNT-induced lung inflammation and fibrosis.ObjectiveTo construct a SWCNT-induced lung fibrosis model in mice and to investigate the protective effect of glycyrrhetinic acid monosaccharide on lung fibrosis in mice.To investigate whether glycyrrhetinic acid monosaccharide alleviates SWCNT-induced pulmonary fibrosis by inhibiting PI3K/AKT and NF-κB anti-inflammatory signaling pathways.MethodsAnimal grouping and drug administration 150 female C57/BL mice of 7-8 weeks old were randomly divided into 4 groups of 30 mice each,and the normal control group was given saline tracheal drip,and the SWCNT(S)control group,S+18β-GAMG dose group and S+GL drug dose group were set up.group),200 mg/kg.d(GL drug dose group),were administered by intraperitoneal injection,and mice were given intraperitoneal injection of drug before tracheal drip of SWCNT for 1h for 28 days,and mice were sampled on 3,7 and 28 days,respectively;SWCNT was dripped into the trachea of C57/BL mice to construct a mouse lung fibrosis model,and lung tissues were collected at different time points to calculate lung coefficients;Detection of pulmonary fibrosis indexes: α-SMA,Vimentin and HYP content measurement by immunohistochemistry;observation of pathological structural changes in the lung at different days by HE staining and pulmonary fibrosis by Masson staining.The contents of IL-6,TNF-α and IL-1β in alveolar lavage fluid of mice were measured by using ELISA kits.To investigate the in vivo anti-inflammatory activity of glycyrrhetinic acid monosaccharide and its protective effect on carbon nanotube-induced pulmonary fibrosis in mice.Western blot method to detect the expression levels of PI3K/AKT/NF-κB signaling pathway-related proteins and reveal its molecular mechanism of anti-pulmonary fibrosis.The levels of NF-κB were observed by immunofluorescence.ResultsThe results showed that glycyrrhetinic acid monosaccharide alleviated singlewalled carbon nanotube-induced pulmonary fibrosis.The results of the study revealed that the HE staining preliminarily revealed that in the single-walled carbon nano group induced mice,compared to the blank group,inflammatory cells infiltrated significantly on the third day,alveolar structure destruction was more obvious,and lung tissue integrity was severely damaged,while the drug group glycopyrrolate monosaccharide treatment group had reduced inflammatory cell infiltration,alveolar structure was structurally intact and less damaged compared to the SWCNT exposed group,and the treatment effect was better than the glycopyrrolate group The ELISA results showed that the contents of IL-6,TNF-α and IL-1β in the lung tissue of mice on the third day were significantly higher in the SWCNT-exposed group compared with the blank control group(P<0.05),while the expression of IL-6,TNF-α and IL-1β in the glycyrrhizic acid monosaccharide treated group compared with the SWCNT-exposed group was decreased(P<0.05)and the effect was better than that of the glycopyrrolate group(P<0.05).Masson and Sirius red staining and HYP test results showed that the pathological results of the blank control group showed intact alveolar structure,while the results of the SWCNT-exposed group showed a significant increase in collagen fiber deposition in mouse lung tissue with increasing time,at day 28,while the glycopyrrolate monosaccharide drug expression in the treated group compared to the SWCNT-exposed group was significantly alleviated and the effect was better than that of the glycopyrrolate group(P<0.05).The results showed that glycopyrrolate monosaccharide alleviated pulmonary fibrosis by inhibiting the pre-PI3K/AKT/NF-κB signaling pathway.To further verify the mechanism of glycyrrhizic acid monosaccharide in alleviating pulmonary fibrosis,we detected the expression levels of PI3K/AKT/NF-κB signaling pathway-related proteins by Western blot method,and found that the expression levels of PI3K/AKT/NF-κB p65 were lower in the blank control group,and the expression levels of PI3K/AKT/NF-κB phosphorylated proteins were significantly higher in the SWCNTexposed group(P<0.05).expression levels were significantly higher in the SWCNTexposed group(P<0.05),whereas the expression of PI3K/AKT/NF-κB phosphorylation was reduced in the glycopyrrolate monosaccharide treatment group compared to the SWCNT-exposed group(P<0.05)and was better than in the glycopyrrolate group(P<0.05).Immunofluorescence(IF)results also showed significantly higher expression of NF-κB p65 compared to the blank control group expression compared to.In contrast,glycyrrhizic acid monosaccharide effectively inhibited the expression of NF-κB p65(P<0.05)and was more effective than the glycyrrhizic acid group(P<0.05).Conclusions1.Glycyrrhizic acid monosaccharide was found to have a protective effect on pulmonary fibrosis in mice in the construction of SWCNT-induced pulmonary fibrosis model.2.It was found that glycyrrhizic acid monosaccharide could alleviate SWCNT-induced pulmonary fibrosis in mice by pre-inhibiting PI3K/AKT and NF-κB signaling pathways.