RESUMO
Aim To explore the effeet of chemogenetic designer reeeptors exclusively activated by designer drugs( DREADD) mediated inhibition of glutamatergic neurons in paraventricular nucleus of hypothalamus (PVN ) on myocardial ischemia-reperfusion injury in mice.Methods Mice were catheterized in PVN by stereotaxic technique, followed by recover}' for three days in individual cages.The mice were then received the inhibitory virus rAAV CaMK E cx-hM4d (Gi)-EG- FP-WPRE-hGHpA or the control vims rAAV CaMK H a - E GF P- W PRE - h GH pA in the PVN nucleus.Three weeks after virus infection, myocardial ischemia-reperfusion injury ( IR) was performed by ligating the left anterior descending coronary artery for 1 h and then releasing it for 2 h.Clozapine N-oxide (CNO) 2 mg •kg 1 was injected intraperitoneally 1 h before IR, to induce inhibition of glutamatergic neurons in PVN by specifically binding to the hM4D receptor ( Gi).TTC staining was used to measure the infarct size, and ELISA was used to measure the serum cTnl concentration.During experiments, the ECG was recorded by PowerLab system.Western blot was used to detect the pro-survival kinase ERK and cleaved caspase-3 proteins in heart tissues, and the expressions of EGFP, CaMKII and c-fos in PVN were examined under fluorescence microscope.Results The glutamatergic neurons in PV N were specifically infected by AAV vectors.When compared with sham group, the ratio of IS/AAR, serum cTnl, c-fos in PVN, and cleaved caspase-3 protein all increased in IR group , but the pERK level decreased.However, hM4D ( Gi) DREADD mediated inhibition of PVN glutamatergic neurons significantly reduced IS/AAR, cTnl concentration and c-fos expression in PVN, as well as the decrease of cleaved caspase-3 and the increase of pERK in heart tissues.Conclusion Chemogenetic DREADD mediated inhibition of glutamatergic neurons in paraventricular nu- cleus of hypothalamus ( PVN) reduces myocardial is- chemia-reperfusion injury in mice.
RESUMO
OBJECTIVE: To investigate the sensitizing effect and mechanism of diosgenin on anti-proliferation activity of mitoxantrone hydrochloride on MDR cells. METHODS: Verapamil was used as positive control. MTT method was used to evaluate the proliferation inhibition effect of diosgenin combined with mitoxantrone hydrochloride on MES-SA/MX2 cells. Western blot method (WB) and RT-qPCR were used to evaluate the effect of diosgeninon protein and gene expression of P-gp respectively. The uptake activity of TMRM was measured by flow cytometry(FCM). ATPase activity was determined by kit. RESULTS: Diosgenin can ehhance proliferation inhibition of mitoxantrone hydrochloride in MDR cell lines (MES-SA/MX2). The reversing index was 2.4 times of verapamil. Diosgenin decreased P-gp protein expression by 22.2% (P<0.01), but had marginal effect on P-gp mRNA. Diosgenin increased the fluorescence intensity of TMRM by 14.5%, and did not affect ATPase activity. CONCLUSION: Diosgenin can increase the sensitivity of mitoxantrone hydrochloride by inhibiting P-gp.