Effectiveness of a hydroxynaphthoquinone fraction from Arnebia euchroma in rats with experimental colitis

AIM:To evaluate the potential effectiveness of hydroxynaphthoquinone mixture(HM)in rats with 2,4,6-trinitrobenzene sulfonic acid(TNBS)-induced colitis.METHODS:Colitis was induced by intracolonic administration of TNBS(80 mg/kg,dissolved in 50%ethanol).Rats were treated daily for 7 d with HM(2.5,5,10 mg/kg)and mesalazine 100 mg/kg 24 h after TNBS instillation.Disease progression was monitored daily by observation of clinical signs and body weight change.At the end of the experiment,macroscopic and histopathologic lesions of rats were scored,and myeloperoxidase(MPO)activity was determined.We also determined inflammatory cytokine tumor necrosis factor(TNF)-αlevel by ELISA,Western blotting and immunochemistry to explore the potential mechanisms of HM.RESULTS:After intracolonic instillation of TNBS,animals developed colitis associated with soft stool,diarrhea and marked colonic destruction.Administration of HM significantly attenuated clinical and histopathologic severity of TNBS-induced colitis in a dose-dependent manner.It abrogated body weight loss,diarrhea and inflammation,decreased macroscopic damage score,and improved histological signs,with a significant reduction of inflammatory infiltration,ulcer size and the severity of goblet cell depletion(all P<0.05 vs TNBS alone group).HM could reduce MPO activity.In addition,it also decreased serum TNF-αlevel and down-regulated TNF-αexpression in colonic tissue.This reduction was statistically significant when the dose of HM was 10 mg/kg(P<0.05 vs TNBS alone group),and the effect was comparable to that of mesalazine and showed no apparent adverse effect.The underlying mechanism may be associated with TNF-αinhibition.CONCLUSION:These findings suggest that HM possesses favourable therapeutic action in TNBS-induced colitis,which provides direct pharmacological evidence for its clinical application.

Glucose Metabolic and Gluconeogenic Pathways Disturbance in the Intrauterine Growth Restricted Adult Male Rats

Objective To explore the molecular mechanism of type 2 diabetes in intrauterine growth restricted adult rats through determination of blood glucose and expression of gluconeogenic enzymes in liver.Methods Male intrauterine growth restriction(IUGR) offspring induced by maternal protein-malnutrition and normal controls were studied.The body weights of offspring rats were weighted from birth to 12 weeks of age.Fasting plasma glucose and insulin levels were determined by glucose oxidase method and enzyme-linked immunosorbent assay(ELISA) respectively at 1 week,8 weeks,and 12 weeks.Peroxisome proliferator-activated receptor-γ coactivator-1α(PGC-1α),phosphoenolpyruvate carboxykinase(PEPCK),and glucose-6-phosphatase(G6Pase) mRNA and protein levels in liver were measured by real time RT-PCR and Western blot in newborn rats(Week 1) and adult rats(Week 12).Results Birth weights of IUGR rats were significantly lower than those of controls until 4 weeks later,when IUGR rats caught up to controls.Between 8 and 12 weeks,the growth of IUGR rats surpassed that of controls.No significant differences were observed in blood glucose and insulin levels at newborn rats between the two groups.However,by the end of 8 weeks IUGR rats developed hyperinsulinemia and high insulin resistance index.At the age of 12 weeks,IUGR rats had mild fasting hyperglycemia.In addition,hepatic PGC-1α mRNA and protein levels as well as hepatic mRNA levels of PEPCK and G6Pase at Week 1 and Week 12 in IUGR rats were all significantly higher than those of controls(P<0.05).Conclusions As a result of intrauterine malnutrition,the expression of gluconeogenic genes is exaggerated in offspring.This change stays through adulthood and may contribute to the pathogenesis of type 2 diabetes.