AIM:To investigate the ameliorative effect of nociceptin/orphanin(N/OFQ)on anxiety-like be-havior in nicotine(NIC)withdrawal-induced rats and its regulatory mechanisms on the expression of neurotransmitters as-sociated with the hypothalamic-pituitary-adrenal(HPA)axis and inflammatory factors.METHODS:Thirty-two adult male Sprague-Dawley rats were randomly divided into 4 groups:normal control group,NIC withdrawal model group,low-dose N/OFQ treatment group,and high-dose N/OFQ treatment group,with 8 rats in each group.To establish NIC with-drawal model,the rats in the NIC model and N/OFQ treatment groups were subcutaneously injected with NIC(0.4 mg/kg),twice a day for 7 consecutive days followed by 3 days of withdrawal.During the withdrawal period,the rats in the low and high-dose N/OFQ treatment groups received intracerebroventricular injection of N/OFQ(1 nmol or 10 nmol)once per day for 3 consecutive days.Ten minutes after the third administration,all rats underwent open filed(OF)and elevated plus maze(EPM)tests to detect behavioral changes.The serum concentrations of corticotrophin-releasing hormone(CRH),adrenocorticotropic hormone(ACTH),corticosterone(CORT),tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β)and IL-6 were measured by ELISA.The mRNA expression levels of TNF-α,IL-1β and IL-6 in the central nu-cleus of the amygdala(CeA)of the brain were detected by RT-qPCR.Histological changes in neuron morphology in the CA1 region of the hippocampus were observed under a light microscope following hematoxylin and eosin(HE)staining.Norepinephrine(NE)levels in the CeA of the brain were determined by HPLC.The protein expression of tyrosine hydroxy-lase(TH)in the CeA of the brain was detected by Western blot.RESULTS:Compared with the NIC withdrawal model group,rats in the low and high-dose N/OFQ treatment groups showed significant increase in the distance and time spent in the central area of the open field(P<0.05 or P<0.01),as well as significant increase in the number of entries and the per-centage of time spent in the open arms of the EPM(P<0.05 or P<0.01).Furthermore,both low and high-dose N/OFQ treatment groups significantly inhibited serum concentrations of CRH,ACTH and CORT in NIC withdrawal rats(P<0.01).N/OFQ administration also significantly reduced the levels of inflammatory cytokines TNF-α,IL-1β,and IL-6 in the serum,as well as expression levels of TNF-α,IL-1β and IL-6 mRNA in the CeA(P<0.05 or P<0.01).The treatment with N/OFQ at both doses significantly alleviated neuronal damage in the CA1 region of the hippocampus and markedly re-duced thelevels of NE and TH protein expression in the CeA of NIC withdrawal rats(P<0.01).CONCLUSION:N/OFQ alleviates anxiety-like behavior in NIC withdrawal rats through mechanisms related to the regulation of HPA axis hormone levels and inflammatory factors.

Objective To investigate the inhibitory effect of Sauchinone(Sch)on renal tissue fibrosis and to explore its mechanism in unilateral ureteral obstruction(UUO)mice.Methods Forty male ICR mice were divided into Sham,UUO-Model,Sch Low-dose,Sch High-dose,and positive control(Val)groups.Mice in the sham group underwent isolation of the left renal ureter without ligation,and mice in the UUO-Model group underwent stripping of the left proximal ureter for double ligation.Starting on day 2 after surgery,the Sch Low-dose group received 10 mg/kg Sch,the Sch High-dose group received 30 mg/kg Sch,and the Val group received 100 mg/kg valsartan by gavage once daily for 4 weeks.At the end of drug administration,serum creatinine(SCr),blood urea nitrogen(BUN),and the inflammatory factors tumor necrosis factor(TNF)-α and interleukin(IL)-6 were measured.Superoxide dismutase(SOD)activity,and malondialdehyde(MDA)and reactive oxygen species(ROS)content were detected in renal tissues.TNF-α and IL-6 mRNA levels were detected in renal tissues by reverse transcription-quantitative polymerase chain reaction.Pathological changes and collagen deposition,as well as transforming growth factor(TGF)-β1,Smad3,and connective tissue growth factor(CTGF)protein expression in mouse renal tissues were detected by hematoxylin and eosin and Masson staining,and immunohistochemistry.Collagen Ⅰ,CTGF,Smad3,nuclear factor erythroid 2-related factor 2(Nrf2),heme oxygenase-1(HO-1),and nuclear factor(NF)-κB protein expression in renal tissues were detected by Western Blot.Results SCr,BUN,TNF-α,and IL-6 were all significantly reduced in Sch Low-dose and Sch High-dose mice compared with the UUO-Model group(P＜0.05 or P＜0.01),while SOD activity was significantly higher and MDA and ROS levels were significantly lower in renal tissues(P＜0.05 or P＜0.01),and TNF-α and IL-6 mRNA in renal tissues were significantly reduced(P＜0.05 or P＜0.01).Microscopic observation of swollen renal tubules with thylakoid hyperplasia and collagen fiber deposition was significantly improved.Immunohistochemistry showed a significant reduction in TGF-β1,Smad3,and CTGF protein expression in renal tissues,and Western Blot showed significantly reduced levels of Collagen Ⅰ,CTGF,Smad3,and NF-κB protein expression(P＜0.05 or P＜0.01),while Nrf2 and HO-1 protein expression levels were significantly elevated(P＜0.05 or P＜0.01).Conclusions The amelioration of renal tissue fibrosis by sauchinone may be mediated via anti-inflammatory and antioxidative stress effects that modulate the expression of pro-fibrotic proteins in the TGF-β1/Smad3 signaling pathway.