OBJECTIVETo establish an easy and repeatable method for determination of pulmonary vascular resistance in normal and pulmonary arterial hypertension (PAH) rats.

METHODSForty-five Sprague-Dawley rats were randomly assigned into three groups: control group, low dose monocrotaline (MCT) group (50 mg/kg) and high dose MCT group (60 mg/kg). Rats in PAH groups received single subcutaneous injection of MCT. We measured pulmonary artery pressure by right heart catheterization using an improved hand-made PE-50 catheter. Cardiac output was calculated through thermodilution method. Pulmonary vascular resistance equals the mean pulmonary artery pressure divided by cardiac output.

RESULTSThe total percentages of success to detect pulmonary artery pressure, cardiac output and pulmonary vascular resistance were 98%, 100% and 96% respectively in 3 groups. Twenty-one days after MCT injection, mean pulmonary artery pressure significantly increased in MCT group compared to control group [(43.1 ± 0.8), (54.8 ± 2.2) vs. (17.4 ± 1.0) mm Hg (1 mm Hg = 0.133 kPa), P < 0.001], and the mPAP was also significantly higher in high dose MCT group than in low dose MCT group (P < 0.001). Cardiac output was significantly lower in PAH rats than in control rats [(77.5 ± 6.9), (71.0 ± 6.7) vs. (126.8 ± 3.9) ml/min, P < 0.001]. Pulmonary vascular resistance was significantly increased in PAH rats compared with control rats [(0.56 ± 0.06), (0.76 ± 0.08) vs. (0.13 ± 0.01) mm Hg×min(-1)×ml(-1), P < 0.001]. There were significant differences in both MCT-treated groups (P = 0.01).

CONCLUSIONSPulmonary vascular resistance in rats could be reliably detected using the improved hand-made PE-50 right heart catheter.

Animals ; Cardiac Catheters ; Hypertension, Pulmonary ; diagnosis ; physiopathology ; Monocrotaline ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Vascular Resistance

To establish an HPLC method for determining components in monocrotalinum liposomes. The results showed a good linear relationship in monocrotalinum liposomes within the concentration range between 1.6-102.4 mg x L(-1) (r = 0.999 8), with RSDs of intra-day precision, inter-day precision, stability and reproducibility of 0.61%, 0.92%, 1.7%, 1.6%, respectively. The recovery rate of monocrotaline was (99.96 +/- 0.50)%. These data indicated that the HPLC method could accurately determine components in monocrotalinum liposomes. Meanwhile, the microcolumn centrifugation method was established to determine the entrapment efficiency of components in monocrotalinum liposomes. As a result, the recovery rate and the blank liposome recovery of free components were (94.44 +/- 0.77)%, (95.86 +/- 0.68 )%, respectively. According to the parallel determination of the entrapment efficiency of three monocrotaline liposomes, their RSD was 4.0%. The data indicated that the microcolumn centrifugation method was an accurate and feasible method for determining the entrapment efficiency of monocrotaline liposomes.
Chromatography, High Pressure Liquid ; methods ; Drug Carriers ; chemistry ; Drug Compounding ; Liposomes ; chemistry ; Monocrotaline ; chemistry

Animals ; Hypertension, Pulmonary ; chemically induced ; physiopathology ; Monocrotaline ; adverse effects ; Rats ; Rats, Sprague-Dawley ; Thrombomodulin ; metabolism

OBJECTIVETo observe the pathological changes in the myocardial and pulmonary tissues in miniature pigs with chronic pulmonary hypertension induced by monocrotaline (MCT).

METHODSTwelve male miniature pigs (weigh 15.0-18.0 kg, aged 4.0-4.5 months) were examined for baseline mean pulmonary artery pressure (mPAP), followed by intraperitoneal injection of 10.0 mg/kg MCT in 10 randomly selected pigs. The mean pulmonary artery pressure at 4 and 8 weeks were determined, and the pathological changes in the myocardial and pulmonary tissues were observed.

RESULTSThe baseline mPAP of normal miniature pigs was 15.19∓0.70 mmHg. At 4 and 8 weeks after MCT injection, the sPAP and dPAP were 19.69∓2.47 mmHg and 25.62∓4.88 mmHg, respectively, and the mPAP increased significantly compared with that of the normal control group (P<0.01). Obvious pathological changes such as pulmonary hypertension and right ventricular hypertrophy were found in the pigs 4 weeks after MCT injection, and at 8 weeks, significant pathological changes occurred including right ventricular fibrosis and thickening of the tunica media of the pulmonary artery.

CONCLUSIONMCT can cause pulmonary hypertension in miniature pigs 8 weeks after drug administration, shown as increased pulmonary artery pressure and pulmonary vascular remodeling.

Animals ; Hypertension, Pulmonary ; chemically induced ; pathology ; Lung ; pathology ; Male ; Monocrotaline ; adverse effects ; Myocardium ; pathology ; Swine ; Swine, Miniature

OBJECTIVETo explore potential divergent glycolytic metabolism gene changes between left and right ventricle in the monocmtaline (MCT) induced pulmonary arterial hypertension (PAH) rat model.

METHODSPAH was induced by a single subcutaneous injection of MCT (50 mg/kg) in rats. Control rats were injected with normal saline. MCT-PAH rats were randomly divided into MCT-2week, MCT-3week and MCT-4week groups (MCT-2w, 3w, 4w). At the end of study, the hemodynamics and right ventricular hypertrophy were compared among groups. The expression levels of proliferating cell nuclear antigen (PCNA) and TdT-mediated dUTP nick end labeling (TUNEL) in left and right ventricular cells were compared. The glycolytic key candidate genes expression was screened between two ventricles.

RESULTSAfter three to four weeks MCT injection, mean pulmonary arterial pressure, right ventricular systolic pressure and right ventricular hypertrophy index were all significantly increased compared to control group (all P < 0.05). Both left and right ventricular morphology and structure changes were observed in all PAH rats and were similar between left and right ventricular cells. Left and right ventricular cells increased while apoptotic cells decreased in proportion to the duration post MCT injection and the PCNA positive cells in the right ventricle were higher than in the left ventricle in rats post 3 and 4 weeks MCT injection (P < 0.05). The HK1, HK2, PDHα1 and LDHA mRNA expression in the left ventricle and LDHA mRNA expression were significantly upregulated after 4 weeks MCT injection compared to control rats (all P < 0.05). Moreover, HK1 mRNA expression in the left ventricle was significantly higher in the MCT-PAH-4w group than in MCT-PAH-3w group (P < 0.05). Immunohistochemistry analysis evidenced increasing HK1 positive cells in both left and right ventricle in proportion to MCT injection time and positive HK1 cells were significantly higher in the right ventricle than in left ventricle of MCT-PAH-3w and MCT-PAH-4w rats. Furthermore, the HK1 protein expression in left ventricular tissue form MCT-PAH-4w group and in right ventricular tissue from MCT-PAH-3w and MCT-PAH-4w groups were also significantly upregulated compared to control group (P < 0.05).

CONCLUSIONSEnergy metabolic shift occurs both in the left and right ventricles in this PAH model. Upregulated HK1 expression appeares earlier in right ventricle compared to left ventricle. Interference on right ventricular glycolysis may be a potential novel therapy target of PAH.

Animals ; Gene Expression ; Heart Ventricles ; metabolism ; Hemodynamics ; Hypertension ; Hypertension, Pulmonary ; metabolism ; Hypertrophy, Right Ventricular ; metabolism ; Lung ; Monocrotaline ; Rats

OBJECTIVETo investigate the fetotoxicity of monocrotaline.

METHODMouse whole embryo culture (WEC) was applied. Post-implantation (8.5 d) mouse embryos were isolated from their mothers and put into the medium of immediately centrifuged serum (ICS) prepared from rats. Different concentrations of monocrotaline (100, 50, 25, 12.5 mg x L(-1)) were added into the WEC. Development (yolk sac diameter, crown-rump length, head length, somite number) and organic morphodifferentiation (yolk sac circulation, allantois, embryonic flexion, heart, brain, optic-otic-olfactory organ, branchial arch, maxillary, mandible, bud) of embryos were observed at 48 h after treatment.

RESULTObvious fetotoxicity could be observed in various monocrotaline treatment groups in a dose-dependent manner. Development of embryos was delayed significantly at dose 12.5-100 mg x L(-1). Malformations were shown in all organic morphodifferentiation indice, especially in opti-otic organ, mandible and bud.

CONCLUSIONMonocrotaline had obvious fetotoxicity in vitro WEC, indicating that exposure of pregnant mice to monocrotaline may have potential risk on fetus.

Animals ; Cell Differentiation ; drug effects ; Culture Media ; Embryo, Mammalian ; drug effects ; physiology ; Female ; Male ; Mice ; Monocrotaline ; toxicity

The pathophysiological implications of aldosterone and adrenomedullin in the cardiac ventricular hypertrophy were examined. Male Sprague-Dawley rats were treated with deoxycorticosterone acetate (DOCA)-salt and monocrotaline (MCT) to selectively elicit left and right ventricular (LV, RV) hypertrophy, respectively. The mRNA expression of aldosterone synthase and adrenomedullin in LV and RV was determined by reverse transcription-polymerase chain reaction. The expression of aldosterone synthase and adrenomedullin was increased in LV, while not altered significantly in RV of DOCA-salt-treated rats. On the contrary, the expression was not significantly altered in LV, but increased in RV of MCT-treated rats. The enhanced expression of aldosterone synthase may be causally related with the development of ventricular hypertrophy, and the increased expression of adrenomedullin may act as a counter-regulatory mechanism.
Adrenomedullin* ; Aldosterone Synthase* ; Aldosterone* ; Animals ; Desoxycorticosterone ; Humans ; Hypertrophy ; Hypertrophy, Right Ventricular* ; Male ; Monocrotaline ; Rats* ; Rats, Sprague-Dawley ; RNA, Messenger

The present study was aimed to explore pathophysiological implications of nitric oxide in the development of left and right ventricular hypertrophy. To induce selective left and right ventricular hypertrophy, rats were made two-kidney, one clip (2K1C) hypertensive and treated with monocrotaline (MCT), respectively. Six weeks later, the hearts were taken and their ventricular tissue mRNA and protein expression of endothelial constitutive isoform of nitric oxide synthase (NOS) were determined by reverse transcription-polymerase chain reaction and Western blot analysis, respectively. In 2K1C hypertensive rats, the expression of NOS mRNA was increased in parallel with its proteins in the left ventricle, but not in the right ventricle. In MCT-treated rats, the expression of NOS mRNA and proteins were proportionally increased in the right ventricle, but not in the left ventricle. These results suggest that the expression of NOS is specifically increased in association with the ventricular hypertrophy, which may be a mechanism counteracting the hypertrophy.
Animals ; Blotting, Western ; Cardiomegaly ; Heart ; Heart Ventricles ; Hypertrophy ; Hypertrophy, Right Ventricular* ; Monocrotaline ; Nitric Oxide Synthase ; Nitric Oxide* ; Rats ; RNA, Messenger

OBJECTIVE: To study the protective effects of ginkgo biloba extract on the right ventricular hypertrophy. METHODS: Seventy-two SD male rats were randomly divided into 3 groups: control group(CON), monocrotaline-induced right ventricular hypertrophy group (MCT) and ginkgo biloba extract treated group (EGB) (n=24 in each group). Group MCT and group EGB were intraperitoneally injected with 2%MCT at the dose of 60 mg /kg on the first day. From the second day, group MCT was injected with 2 ml 0.9% sodium chloride, and 60 mg/kg ginkgo leaf extract was administered to the stomach in group EGB. The control group was injected with 2 ml 0.9% sodium chloride on the first day. After 3 weeks, in each group,cardiac hemodynamic changes were measured, heart weight index was calculated, and myocardial pathological changes were observed by HE staining. The expression of TRPC6 was detected by real-time polymerase chain reaction (real-time -PCR) and Western blot. RESULTS: Compared with the control group, the right ventricular systolic pressure (RVSP) was increased significantly in the MCT group(P＜0.01), the maximum or decline rate of descent (RV ±dp/dt) of the right ventricle pressure was increased significantly(P＜0.01), while the EGB group had the same trend as all the indexes in the group MCT, but the amplitude of all indicators in group EGB were decreased significantly than those of group MCT(P＜0.01), and the right ventricular hypertrophy index (RVMI) in group EGB was significantly lower than that in group MCT(P＜0.01).Group MCT showed typical myocardial hypertrophy performance by HE staining, and the right ventricular myocytes in group EGB were significantly improved than that in group MCT, and the mRNA and protein expression levels of TRPC6 in the right ventricle of group MCT and group EGB were increased(P＜0.01), while the EGB group was significantly lower than that of the MCT group(P＜0.01). CONCLUSION Ginkgo biloba extract may inhibit the signal pathway of CaN / NFAT in cardiac myocytes by reducing the expression of TRPC6 protein, and then play an early protective effect on myocardial hypertrophy.
Animals ; Hypertrophy, Right Ventricular ; chemically induced ; drug therapy ; Male ; Monocrotaline ; Plant Extracts ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo observe the effect of total ginsenosides (TG) on right ventricular hypertrophy induced by monocrotaline (MCT) in rats, and study its relationship with the nitric oxide pathway.

METHODMale Sprague Dawley rats were randomly divided into the control group, the MCT model group, TG-treated (20, 40, 60 mg kg-1 d-1) groups, and the L-arginine (L-arg) th NO release, T + L-N and L-a + L-N groups were wi th NOS into study TG's effect 200 mg kg-1 d-1 group. Besides, and its relationship wi also set, intraperitoneally injected with TG 40 mg kg-1 d -1 and L-arg 200 mg kg-1 - d-1, and orally administered hibitor L-NAME 20 mg kg-1 d-1. After all of the groups were given drugs for 18 d, their right ventricular peak systolic pressure (RVSP) ventricular hypertrophy index (RVHI) and RVW/BW were determined. Ultra-structure of myocardial cells was observed with transmission electron microscope. The NO2 -/NO3 - content in myocardial tissues were detected with the nitrate reduction method. ANF and eNOS mRNA expressions in right ventricle tissues were detected by using real-time RT-PCR.

RESULTLow, middle and high doses of TG and L-arg preventive administration could significantly reduce RVSP, RVHI, RVW/BW and ANF mRNA expressions (P < 0. 05) , and ameliorate cellular mitochondrial swelling and degeneration. L-NAME could prevent the effect of L-arg on above indexes, whereas L-NAME of the same dose could not impact the reducing effect of TG 40 mg kg -1 on above indexes. TG 60 mg kg -1 could raise eNOS mRNA expression, but TG 20 mg kg-1 and 40 mg kg-1 showed no effect.

CONCLUSIONTG can significantly attenuate MCT-induced right cardiac hypertrophy in rats. Its anti-hypertrophic effect is partially realized through NO.

Animals ; Ginsenosides ; therapeutic use ; Hypertrophy, Right Ventricular ; chemically induced ; drug therapy ; metabolism ; Male ; Monocrotaline ; toxicity ; Nitric Oxide ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley