ABSTRACT
Objective:To investigate the effect and mechanism of short-chain fatty acids (SCFAs) on the side-effect of tacrolimus on blood glucose.Methods:The C57BL/6 mice were treated with tacrolimus orally (10 mg/kg, tacrolimus group), tacrolimus plus 150 mmol/L sodium butyrate and isovalerate mixed solution (SCFAs group), broad-spectrum antibiotics (antibiotic group), and tacrolimus plus broad-spectrum antibiotics (tac&abx group). After 8 weeks intervention, the fasting blood glucose (FBG), oral glucose tolerance test (OGTT), hemoglobin A1C (HbA1c) were tested as indicators of glucose metabolism, and the gut microbiota, SCFAs concentration in the ileocecal, serum glucagon-like peptide-1 (GLP-1), fasting serum insulin, and GLP-1 expression in intestinal mucosa were performed for intestinal-glucose metabolism mechanism.Results:The FBG and HbA1c were significantly increased in tacrolimus group[(7.31±0.97)mmol/L, (8.34±1.12)%] than control group [(5.23±0.30)mmol/L, (4.32±0.80)%, all P<0.05], which remained normal in antibiotic group [(4.92±0.31)mmol/L, (5.61±0.98)%)], tac&abx group[(5.95±0.37)mmol/L, (4.56±0.26)%] and SCFAs groups [(5.87±0.68)mmol/L, (5.07±1.79)%]. The OGTT in the tacrolimus group showed glucose tolerance impairment, while other groups remained normal. The ileocecal butyric acid and isovaleric acid concentrations in the tacrolimus group were (722.3±262.2) μg/g and (10.0±5.1)μg/g, lower than the control group[ (1 321.3±165.5) μg/g, (19.7±3.6)μg/g, P<0.05]. The above acids in the SCFAs group remained normal as in the control group [(1 375.7±451.6) μg/g, (24.5±11.5)μg/g)]. The fasting serum insulin in the tacrolimus group decreased significantly to (3.2 ± 0.6)mIU/L, compared with control[ (4.4±0.9) mIU/L]and SCFAs groups [(7.0±1.1) mIU/L]. The GLP-1 test indicated a significant decrease in the tacrolimus group[ (4.7±2.9)pg/ml, P<0.05] compared with the SCFAs group and control group [(42.5±19.9) pg/ml, (33.1±9.1) pg/ml]. Conclusions:Tacrolimus affects glucose metabolism through the SCFAs-associated GLP-1 pathway in the intestine, and oral supplementation with mixed SCFAs provides a new insight for the prevention and treatment of tacrolimus-induced hyperglycemia in transplant recipients.
ABSTRACT
Objective To investigate the effects and possible mechanisms of nicorandil on lung injury of the collapsed lung in one-lung ventilation.Methods Twenty-four clean Japanese big-ear rabbits were randomly divided into sham group (group S) (two-lung ventilation + thoracotomy),negative control group (group C) (one-lung ventilation + thoracotomy + saline),nicorandil group (group N) (one-lung ventilation+thoracotomy+nicorandil) and antagonist group (group J) (onelung ventilation+ thoracotomy+ nicorandil+ glyburide) equally.Mechanical ventilation was implemented through self-made double-lumen endotracheal tube after intravenous induction through ear marginal vein.Intravenous maintenance medicine was infused by trace injection pump after anesthesia induction.Thoracic surgery was simulated through one-lung or two-lung ventilation determined by auscultation,bubble test and direct observation.Then wet and dry weight ratio (W/D) and content of MDA were measured after non-ventilatory lung was processed and preserved.The expression of Akt,p-Akt and NF-κB protein in non-ventilatory lung tissue were detected by Western-blot in all groups.Results In respects of W/D and content of MDA,the other three groups had significant differences compared with group S (P ＜ 0.05).It was significantly lower in group N than in group C (P ＜0.05),and it was significantly higher in group J than in group N (P＜0.05).The expressions of pAkt protein and p-Akt/Akt in group N were significantly higher than those in group S and group C (P＜0.05).Those of group J were significantly lower than group N (P＜0.05).Compared with group S,the expression of NF-κB protein in group C was significantly higher (P＜0.05).That of group N was significantly lower than that of group C (P＜0.05).But that in group J was higher than that in group N (P ＜ 0.05).Conclusion Nicorandil has a protective effect on the collapse and inflation of non-ventilatory lung in rabbits under one-lung ventilation,acting on mitoKATP through PI3K/Akt,and down-regulating NF-κB to reduce IR-induced lung injury.