| Background and objective:Depression is a serious harm to human physical and mental health of mental illness,characterized with low mood now.With the quickening pace of life as well as increasing social pressure,there is trend of increasing the incidence of depression significantly every year.Clinical studies have shown the depression with increased risk of type 2 diabetes,but the effective treatment strategies should be strengthened.Banxia-Houpu decoction is a traditional Chinese medicine(TCM)of classic prescription.Its clinical practice has been used for effective treatment of depression and other diseases.Banxia-Houpu decoction can improve patients with diabetes with blood glucose levels,suggesting that Banxia-Houpu decoction may have potential advantages in the intervention of depression with diabetes risk.The liver is a major organ for glucose metabolism.The liver inflammation hinders normal insulin signaling transduction pathway and cause insulin resistance.Our research group has established a rat model of a chronic unpredictable mild stress(CUMS)induction,a simulation of depression.This animal model showed a depressive-like behavior and impaired oral glucose tolerance,but the underlying mechanisms still need further explore.Many studies have demonstrated that Banxia-Houpu decoction has antidepressant effects in a variety of animal models of depression,but whether its improvement of impaired glucose tolerance and possible way are necessary to explore.This thesis explored to investigate the effects of CUMS on liver Nod like receptor protein of 3(Nod-like recepter protein 3,NLRP3)inflammasome,interleukin-1 beta(IL-1β)and insulin signal,with pathological characteristics of impaired glucose tolerance in the animal model of depression.And based the above,this thesis importantly investigated and analyzed the effects of Banxia-Houpu decoction on impaired glucose tolerance,liver inflammation and insulin signal impairment in CUMS rats.These investigations may preliminarily descript the possible way to reduce depression with type 2 diabetes risk by Banxia-Houpu decoction.Methods:Sixty adult male Wistar rats(weighing 180-200 g),were randomly assigned to normal control group(Non-CUMS),model control group(CUMS),Banxia-Houpu decoction group(CUMS+BXHP,3.29 and 6.58 g/kg)and fluoxetine hydrochloride positive drug control group(CUMS+Flu,10 mg/kg).Except the normal control group,each group with chronic unpredictable mild stress method for 6 weeks of modeling to the rats,were orally given different doses of Banxia-Houpu decoction and fluoxetine hydrochloride for next 6 weeks.Normal control group and model control group were given the same volume of saline,respectively.In modeling,and during administration,1%sucrose water intake for each group was determined for 1 h.which evaluated depressive-like behaviors in rats,with changes in the appearance,body weight and hair color.In rats with drug treatment last for 0.5 h,glucose tolerance test(OGTT)was carried out to analyze glucose tolerance.Blood samples and liver tissues were collected.ELISA kits were used to determine serum corticotropin-adrenal cortical hormone releasing factor(CRF),corticosterone,IL-1βand insulin levels,respectively.Intelligent blood glucose meter detection was used to assay blood glucose levels in rats.Serum glutamic pyruvic transaminase(ALT)activity was determined with the kit of enzymatic detection.Hematoxylin&eosin(HE)staining detection was used to analysis animal liver tissue inflammation.Western Blotting was used to examine liver protein levels of insulin signaling pathway key proteins related to insulin receptor(IR),P-IR,Tyr sites of insulin receptor substrates IRS1(Tyr),P-IRS1(Tyr),Ser sites of insulin receptor substrates IRS1(Ser)and P-IRS1(Ser),as well as NLRP3,apoptosis associated speck like protein(ASC)and Caspase-1 in animals.Results:Compared with the normal control group,animal weight loss and sucrose intake were significantly reduced(p<0.001)in CUMS model control group.Compared with CUMS model control group,Banxia-Houpu decoction(3.29 g/kg:p<0.001;6.58 g/kg:p<0.001)and fluoxetine hydrochloride(p<0.001)significantly increased the intake of animal sugar water,but no obvious change on body weight.Serum CRF and corticosterone levels were significantly increased also in CUMS model(p<0.01),showing the activation of the HPA axis.Banxia-Houpu decoction significantly reduced serum levels of CRF(3.29 g/kg:p<0.001)and corticosterone(3.29 g/kg:p<0.05;6.58 g/kg:p<0.05)in this animal model,further demonstrating that Banxia-Houpu decoction reduced the HPA axis activation.Under this experimental condition,the effect of fluoxetine hydrochloride was not obvious.Serum insulin levels were no significantly change in CUMS rats.OGTT experiment results also confirmed that this animal model showed impaired glucose tolerance(p<0.05).6.58 g/kg of Banxia-Houpu decoction was found to improve the glucose tolerance impairment(p<0.05),and increase serum insulin levels with a trend but not significant in CUMS rats.Fluoxetine hydrochloride also had a similar effect.These results suggested that Banxia-Houpu decoction and fluoxetine hydrochloride might reduce the risk of depression with diabetes.Secondly,Furthermore,this thesis found that IR protein levels were decreased significantly(p<0.05),P-IR/IR(Tyr)protein levels were increased significantly(p<0.01),but IRS1 protein levels were no obvious change.But P-IRS1/IRS1(Ser)protein levels were increased significantly(p<0.01),and P-IRS1(Tyr)/IRS1 protein levels were decreased.3.29 g/kg Banxia-Houpu decoction remarkably up-regulated liver P-IR and P-IRS1(Tyr)(p<0.05),but failed to alter IRS1(Ser)protein levels in CUMS rats.6.58 g/kg of Banxia-Houpu decoction remarkably increased liver protein P-IR(p<0.05)and P-IRS1(Tyr).These results suggested that Banxia-Houpu decoction and fluoxetine hydrochloride might regulate liver insulin signaling transduction and alleviate glucose tolerance impairment in CUMS animals.Furthermore,compared with the normal group,serum ALT activity was significantly increased(p<0.01)in CUMS rats.HE staining showed obvious inflammatory cell infiltration in liver tissue of animal model.Further study found that,compared with the normal control group,liver protein levels of NLRP3(p<0.05),ASC(p<0.001)and Caspase-1(p<0.01)as well as IL-1β(p<0.001)were increased significantly in CUMS rats.Banxia-Houpu decoction reduced these liver protein levels of NLRP3(3.29 g/kg:p<0.05;6.58 g/kg:p<0.01),ASC(3.29 g/kg:p<0.001;6.58 g/kg:p<0.01),Caspase-1(3.29 g/kg:p<0.001;6.58 g/kg:p<0.01),and IL-11β(3.29 and 6.58 g/kg:p<0.001)in CUMS rats.Fluoxetine hydrochloride also significantly reduced liver protein levels of NLRP3(p<0.001),ASC(p<0.01),Caspase-1(p<0.01)and IL-1β(p<0.01)in this animal model.These results suggested that Banxia-Houpu decoction and fluoxetine hydrochloride reduced CUMS-induced liver NLRP3 inflammasome activation and IL-1β levels,to improve liver function and alleviate liver inflammation,and then regulated liver insulin signaling transduction to alleviate glucose tolerance impairment in CUMS animals.Conclusion:(1)The CUMS rat model of depression showed liver NLRP3 inflammasome activation,and then enhanced IL-1β secretion to cause tissue mild inflammation.This inflammatory signaling inhibited normal transduction of hepatic insulin signaling,which may be one of the pathological pathways to mediate glucose tolerance damage in CUMS rat model of depression.(2)Banxia-Houpu decoction improved depressive-like behavior and increased glucose tolerance in CUMS rat model of depression.These results suggest that Banxia-Houpu decoction may have intervention effects on the risk of depression with diabetes.(3)Banxia-Houpu decoction effectively inhibited liver NLRP3 inflammasome activation and decreased IL-1β levels in CUMS rat model of depression,thereby improving mild liver inflammation and protecting the normal transduction of hepatic insulin signaling.These effects may be one of mechanisms by which Banxia-Houpu decoction effectively improve glucose tolerance impairment in this animal model. |
