| Objective:The aim of this study was to characterize the effects of Gatifloxacin(GAT),a quinolone drug,on the imbalance of blood glucose homeostasis in the body,to elucidate the effect of Portulaca oleracea L.on the abnormal blood glucose caused by GAT,and to reveal the molecular mechanism of Portulaca oleracea L.in improving the imbalance of blood glucose homeostasis caused by GAT from the perspective of hepatic glucose metabolism.Methods:In this study,C57BL/6J mice(male,8 weeks old)and db/db mice(male,8 weeks old)were separately used as normal and diabetic animals,and each was randomly divided into 4 groups,Control group(CN),Gatifloxacin group(GAT),Gatifloxacin+Portulaca oleracea L group(GAT+POL),Portulaca oleracea L control group(CN+POL).The effects of gatifloxacin on blood glucose homeostasis in normal and diabetic animals were investigated by observing the changes of blood glucose in mice after single gavage of gatifloxacin(100 mg/kg,i.g.),after 7 consecutive days of gavage(1 times/day)and after 3 days of discontinuation of gatifloxacin.And the intervention effect of POL on gatifloxacin-induced blood glucose abnormalities was investigated by observing the changes in blood glucose levels in mice after the administration of POL(0.4 g/mL,i.g.)2 h before gatifloxacin gavage.On this basis,the effects of gatifloxacin on insulin resistance and the interventional effects of POL were investigated by measuring the serum levels of GLU,INS and GCG in mice and calculating the insulin resistance index and sensitivity index;The effects of gatifloxacin on the lipid metabolism of mice and the intervention of POL were investigated by measuring the serum HDL-C,LDL-C,T-CHO and TG contents of mice.The effects of gatifloxacin on the morphology and function of mouse liver tissues and the interventional effect of POL equivalens were investigated by measuring the serum ALT and AST activity,the histopathological changes of liver by HE staining and the distribution of liver glycogen by PAS staining.In addition,the expression of insulin signaling pathway-related proteins mTOR,PI3K-p110,PI3K-p85,PTP1B,SREBP1c,AKT-1,GLUT2 and hepatic glycogen synthesis and catabolism-related proteins GSK3β,GS and PYGL in mouse liver tissues were analyzed by Western blot to elucidate the molecular mechanisms by which POL amarus ameliorates gatifloxacin-induced glucose abnormalities.Results:1.Abnormal blood glucose changes caused by gatifloxacin and the intervention effect of POLA single treatment with gatifloxacin resulted in a short period of hypoglycaemia in normal mice and an increase in blood glucose in diabetic mice;7 days of continuous administration of gatifloxacin resulted in an abnormal increase in blood glucose in diabetic mice,but the effect on blood glucose in normal mice was not obvious;the increase in blood glucose in normal mice caused by gatifloxacin remained after 3 days of discontinuation of the drug.The effect of gatifloxacin on normal mice was better than that on diabetic mice.2.Mechanisms of gatifloxacin-induced imbalance of glucose homeostasis in the body and the pathway of action of POL(1)Changes in general condition and body weight of mice:Gatifloxacin and POL had no significant effect on the general condition and body weight of mice.(2)Insulin resistance:In normal mice,gatifloxacin caused a significant increase in the insulin resistance index(P<0.001),while the insulin resistance index was significantly reduced after the POL intervention(P<0.001).In diabetic mice,gatifloxacin did not have a significant effect on the insulin resistance index(P>0.05),while the insulin resistance index was reduced after POL intervention(P<0.05).(3)Lipid metabolism:In normal and diabetic mice,gatifloxacin had no significant effect on serum HDL-C but significantly reduced LDL-C(P<0.01),while HDL-C and LDL-C levels did not change significantly after the intervention with POL.Gatifloxacin and POL had no effect on T-CHO and TC levels in normal and diabetic mice.(4)Pancreatic tissue morphology and function:In normal mice,gatifloxacin caused significant morphological and functional damage to the pancreatic tissue.In diabetic mice,gatifloxacin aggravated pancreatic histopathy in diabetic mice.The morphological and functional impairment of the pancreas caused by gatifloxacin was significantly improved after the intervention of POL equinus.(5)Histomorphological function of liver:Gatifloxacin significantly increased the serum ALT and AST levels in normal mice and diabetic mice(P<0.01).The ALT and AST of normal mice were significantly reduced(P<0.01)and those of diabetic mice were slightly reduced(P>0.05)after POL intervention.Gatifloxacin caused significant damage to liver tissue in both normal and diabetic mice.The liver tissue damage caused by gatifloxacin was significantly reduced after the intervention with POL equivalens.3.Molecular mechanism of glucose homeostasis imbalance due to gatifloxacin in the regulation of hepatic glucose metabolism by POL equinus(1)Hepatic insulin signaling pathway:Gatifloxacin increased the expression of insulin signaling pathway proteins PI3K-p110 and PI3K-p85 and decreased the expression of PTPIB in the liver of normal mice(P<0.01);increased the expression of insulin signaling pathway proteins PI3K-p110,PI3K-p85,AKT1 and GLUT2 in the liver of diabetic mice(P<0.05).The expression of insulin signaling pathway proteins mTOR,PI3K-p110,AKT1,GLUT2 in the liver of mice in the GAT group was significantly reduced by POL(P<0.05).(2)Hepatic glycogen synthesis and catabolism:Gatifloxacin caused an increase in hepatic glycogen secretion in mice,and POL significantly reduced the increase in hepatic glycogen synthesis caused by gatifloxacin;gatifloxacin caused an increase in the expression of GSK3β,a protein related to hepatic glycogen synthesis and catabolism,in the liver of diabetic mice(P<0.01);Amaranthus significantly reduced the expression of GSK3β,a protein related to hepatic glycogen synthesis and catabolism,in the liver of mice in the GAT group(P<0.05).Conclusion:1.In normal mice,a single dose of gatifloxacin resulted in an abnormal increase in blood glucose at 0.25h,with significantly greater fluctuations over 8 hours;after one week of continuous administration of gatifloxacin,blood glucose fluctuations were not significant;after 3 days of discontinuation,blood glucose increased significantly.In diabetic mice,a single dose of gatifloxacin resulted in an abnormal increase in blood glucose with significantly greater fluctuations over 8 h.After one week of continuous administration of gatifloxacin,blood glucose increased significantly at 4 h and 6 h with significant fluctuations over 8 h.After 3 days of discontinuation,blood glucose did not differ from that of the CN group.Gatifloxacin was able to slow down the fluctuation of blood glucose in mice after a single administration of gatifloxacin,significantly suppress the increase of blood glucose caused by gatifloxacin,and reduce blood glucose to the level of the CN group.2.Gatifloxacin activates the INS-mediated PI3K/AKT/mTOR signalling pathway in mouse liver tissues to promote the synthesis of hepatic glycogen in the liver.Gatifloxacin activates the expression of PYGL to catabolize glycogen in the liver,and GSK3β to promote glycogen synthesis.The combination of the two causes an imbalance in hepatic glucose homeostasis and abnormal fluctuations in blood glucose in mice.3.POL activates PYGL to promote glycogenolysis;it also inhibits the expression of GSK3β and GS to prevent glycogen synthesis,thus maintaining glucose homeostasis in the body.By inhibiting the disruption of glycogen synthesis and catabolism in diabetes caused by gatifloxacin,POL maintains the balance of glucose metabolism in the liver and maintains glucose homeostasis.POL significantly reduces mTOR levels elevated by gatifloxacin,inhibits the synthetic process of gluconeogenesis and improves the abnormalities of gluconeogenesis caused by gatifloxacin. |
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