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AIM: To study the effects of metformin on the pressure overload-induced cardiac hypertrophy in rats. METHODS: Transverse aortic constriction (TAC) model of rat was made through laparotomy. One week after TAC surgery, the rats were randomly divided into 5 groups (n=8 in each group) and were administered with the corresponding drugs orally every day for 8 weeks: sham group (sham surgery, administered with 2 mL distilled water);TAC group (TAC rats, administered with 2 mL distilled water);metformin(MET) group (TAC rats, administered with MET at dose of 300 mg·kg~(-1)·d~(-1));MN group [TAC rats, administered with MET at dose of 300 mg·kg~(-1)·d~(-1) plus NOS inhibitor, NG-nitro-L-arginine methyl ester (L-NAME) 50 mg·kg~(-1)·d~(-1)] and L-NAME group (TAC rats, administered with L-NAME at dose of 50 mg·kg~(-1)·d~(-1)). After treated for 8 weeks, the echocardiography, hemodynamics, the ratio of heart weight to body weight (HW/BW) and histological examination of the heart were performed. The levels of myocardial AMP-activated protein kinase subunit α (AMPKα), p-AMPKα~(Thr172), endothelial nitric oxide synthase (eNOS) and p-eNOS~(Ser1177) were detected by Western blotting. Plasma and myocardial nitric oxide (NO) were detected biochemically. RESULTS: After 8 weeks treatment, the wall thickness of left ventricle, the heart weight/body weight ratio (HW/BW), and the left ventricular myocardial perivascular fibrosis and myocardial interstitial fibrosis of the animals in TAC group were significantly increased as compared to those in sham rats. Treatment with MET for 8 weeks significantly attenuated left ventricular hypertrophy and improved cardiac function in TAC rats. These effects of MET were mostly abolished by L-NAME. Molecular biology and biochemical testing revealed that the levels of left ventricular myocardial p-AMPKα~(Thr172) and p-eNOS~(Ser1177), as well as the levels of myocardial and serum NO were significantly increased in MET group. CONCLUSION: Long-term MET treatment significantly inhibits the cardiac hypertrophy and the myocardial fibrosis and improves the cardiac functions in pressure-overload rats. The anti-hypertrophic effects of MET may be mediated via activation of AMPK-eNOS signaling pathway.
ABSTRACT
[Objective] To observe the effect of stanozolol on proliferation and differentiation of cultured growth plate chondrocytes in vitro.[Methods] At 3 week of age,Sprague–Dawley rats received 2.5 mg/kg in slow-released GnRHa (triptorelin) which was repeated every 2 weeks for 2 times,at 7-week old.The tibial growth plate cartilage were aseptically dissected and tripsin and EDTA digested for 0.5 h,then collagenase digested for 3 h at 37 ℃.Chondrocytes were cultured in DMEM:F12 medium for 48 h,the cells were starved for 24 h in serum-free DMEM:F12 medium before stanozolol treatment.In dose-effect groups,chondrocytes were incubated in serum-free media in various concentrations of stanozolol for 48 h.In time-course groups,chondrocytes were incubated in serum-free media in various times of stanozolol (10-8 mol/L).immunohistochemical staining of collagen Ⅱ,Ⅹ,PCNA,and MTT were conducted.[Results] The results of MTT,PCNA,and typeⅡcollagen synthesization demonstrated stanozolol enhanced the proliferation of the chondrocytes,time-course studies had shown that the proliferation were maximally stimulated by stanozolol after 2 or 3 days of incubation and decreased again after longer periods of incubation.Stanozolol stimulated the proliferation of the chondrocytes dose-dependently at 10-11 mol/L and 10-8 mol/L,maximally stimulatory concentrations of Stanozolol was 10-9 ～ 10-8 mol/L,and decreased again after higher concentration of stanozolol.Stanozolol did not stimulated type X collagen synthesization from 10-11 mol/L ～ 10-8 mol/L,but experiments showed that type X collagen was already stimulated after incubation in Stanozolol (10-7 ～ 10-5 mol/L).Time-course studies had shown those typeⅩcollagen synthesizations were stimulated by stanozolol after 4 ～ 5 days of incubation.[Conclusion] Stanozolol enhances the proliferation of chondrocytes of pubertal female rat treated with GnRHa in vitro (time-course- dependent and concentration -dependent).
ABSTRACT
<p><b>BACKGROUND</b>To detect quantitatively HCMV DNA in peripheral blood leukocytes to monitor the status of HCMV infection, evaluate the effectiveness of antiviral treatment with ganciclovir (GCV) combined with intravenous immunoglobulin (IVIG) and find out the relationship among the HCMV DNA levels, the state of infection and the clinical outcome.The long-term goal of the study was to establish a molecular diagnostic standard for HCMV infection in children.</p><p><b>METHODS</b>45 cases of suspected HCMV-infected children were examined by PCR, ELISA and fluorescent quantitative (FQ)-PCR, respectively. Twenty five HCMV hepatitis cases of the 45 were randomly assigned to a treated group or a control group. Both groups were treated with prednisone, glucurone, Luminal and Xiaoyanlidanpian. But the treated group was given with GCV+IVIG in addition. Each infant of the two groups was checked with FQ-PCR at the five time points.</p><p><b>RESULTS</b>The positive rates of PCR, ELISA and FQ-PCR were 60.00%, 33.33% and 66.67%,their sensitivities were 84.38%, 46.88% and 93.75%, respectively. There was no significant difference in viral DNA copy numbers between the two groups before being treated (P>0.05), but there was significant difference between HCMV hepatitis and normal infants (P<0.001). Although viral load of both groups decreased in both groups, the viral load of the treated group decreased more significantly. The level of HCMV DNA fell to 103 copies/ml at second time point while that of the control group fell to the same level after third time point. The differences between the two groups at each time point were statistically significant (P<0.001). The results of 135 person times testing indicated that 103 copies/ml of FQ-PCR can be taken as a critical value for prediction of active HCMV infection.</p><p><b>CONCLUSIONS</b>FQ-PCR may be one of the effective methods for diagnosis of HCMV disease; it can offer a key index in the diagnosis of HCMV active infection; dynamic detection of HCMV viral load can play a role not only in monitoring antiviral therapy, but also in evaluating the development and prognosis of HCMV disease.</p>