The Mechanisms Of Olanzapine-induced Hyperprolactinemia And Liver Injury And Its Intervention By Paeoniflorin

BackgroundThe soaring global incidence of mental illness has led to the abuse of antipsychotic drugs.The atypical antipsychotic drug olazapine(Ola)is widely used in clinical practices.However,Ola can cause hyperprolactinemia(HPRL,a hypothalamic-pituitary axis reproductive endocrine disorder syndrome)and liver injury.Nevertheless,the underlying mechanism remains still largely unknown.In recent years,studies have shown that in addition to the dopamine D2 receptor(D2R),transforming growth factor(TGF-?1)system signals are also closely related to secretion of prolactin(PRL)in pituitary.Various reasons can cause damage to the anti-inflammatory factor nicotinic acetylcholine receptor(?7nAchR)signal,and then leading to liver injury.Therefore,TGF-?1 and ?7nAchR signals are considered as important new targets for the treatment of HPRL and liver injury.A traditional Chinese herbal formula Paeoniae-Glycyrrhiza Decoction is effective in treating HPRL and liver injury.We have proved that Yiru Tiaojing Granules,a Nanfang Hospital preparation which containing Paeoniae-Glycyrrhiza Decoction,has a significant effect on the treatment of HPRL.Paeoniflorin(PF),one of the main active ingredients of Radix Paeoniae alba,can inhibit PRL secretion in prolactinoma cells.However,its mechanism still needs to be further studied.ObjectiveBased on the TGF-?1 and ?7nAchR signaling pathways,the molecular mechanisms of HPRL and liver injury induced by Ola and the intervention of PF were explored.These results will provide a scientific basis for preventing side effects caused by Ola and the treatment of PF.Methods1.Animal model and treatmentsFemale SD rats were randomly divided into 5 groups as follows:control,Ola,Ola+Bro,Ola+low dose of PF(10 mg/kg)and Ola+high dose of PF(50 mg/kg).HPRL in female rats was induced by oral administration of ola(5 mg/kg,once daily,x13 weeks).The rats were co-treated orally with Bro(1 mg/kg,a D2R agonist)or paeoniflorin(10 and 50 mg/kg).Fasting blood was collected at week 12.At week 13,all animals were fasted(overnight),euthanized by prompt dislocation of the neck vertebra under anesthesia 10 minutes after insulin injection.The organs were collected,flash frozen in liquid nitrogen,and then stored at-80? degree for subsequent determination of protein and gene expression.2.Cell model and treatmentThe CCK-8 methods was used to determine the toxicity of drugs on MMQ cells.Then appropriate concentrations were selected for experiments.Cells treated with each drug were cultured for 24 hours,then the culture fluid was collected to measure PRL concentration.Cell proteins were extracted to detect protein and gene expression.3.Determination of relevant parametersBlood biochemical parameters were determined by enzymatic or ELISA methods.Hepatic,pituitary and hypothalamus gene/protein expression were analyzed by Real-time PCR/Western blot.Results1.Plasma PRL concentration and the protein expression of PRL in hypothalamus and pituitary were increased by Ola(P<0.05).Also,Ola down-regulated the expression of D2R,TGF-?1 and its downstream signaling proteins in pituitary and hypothalamus(P<0.05),but had no effect on plasma TGF-?1 concentration and liver TGF-?1-related signaling protein expression.High-dose of PF improved the abnormalities above caused by Ola.The results of MMQ cells are consistent with those of rats.2.Ola caused increase plasma ALT and AST levels in rats that inducing liver injury.In addition,Ola inhibited the expression of ?7nAchR protein in the liver,causing an inflammatory response,leading to increased phosphorylation of liver proteins IRS-1 Ser307 and IRS-2 Ser731 thus liver insulin resistance occurred.PF improved the changes of the protein expressions above caused by Ola.The results suggest that PF improves the IRS/PI3K/Akt signaling pathway by increasing the expression of?7nAchR,thereby alleviating the inflammatory response and liver injury caused by Ola.Conclusions1.Ola caused HPRL by reducing central D2R and TGF-?1 system signals.Ola weakened liver ?7nAchR signals,activated inflammatory pathways,and induced liver injury.2.PF improved the HPRL and liver injury caused by Ola by repairing the central D2R and TGF-?1 system and liver ?7nAchR signal damage.