Effect of Guizhitang with Different Proportions of Cinnamomi Ramulus and Paeoniae Alba Radix in Regulating TGF-β1/Smads Signaling Pathway and Chronic Inflammation and Alleviating Myocardial Fibrosis in Salt-sensitive Hypertensive Rats / 中国实验方剂学杂志

<b>Objective::To observe the effect of Guizhitang with different proportions of Cinnamomi Ramulus and Paeoniae Alba Radix on the expressions of transforming growth factor-<italic>β</italic>₁(TGF-<italic>β</italic>₁)/Smads signaling pathway and interleukin-10(IL-10), IL-6 and tumour necrosis factor-<italic>α</italic>(TNF-<italic>α</italic>)related inflammatory cytokines in salt-sensitive hypertensive rats, in order to explore the mechanism of Guizhitang in improving myocardial fibrosis in salt-sensitive hypertensive rats. <b>Method::Totally 40 male 6-week-old salt-sensitive rats were randomly divided into 5 groups: the normal control group, the model group, the 1∶1(RC/peony)Guishao group, the 1∶2 Guishao group, and the 2∶1 Guishao group, with 8 in each group. The normal control group was fed with normal salt diet, while the other four groups were fed with high-salt diet. After 4 weeks of feeding, the rats were given intragastric administration, the normal control group and the model group were given the same amount of normal saline, and the 1∶1 Guishao group, the 1∶2 Guishao group and the 2∶1 Guishao group were given 4.0, 5.5, 5.5 g·kg^-1 of Guizhitang by gavage for 4 weeks. Blood pressure was measured once a week, left ventricular end systolic diameter(LVESD), left ventricular end diastolic diameter (LVEDD), left ventricular ejection fraction (LVEF) and left ventricular short axis shortening fraction (LVFS) were detected by using echocardiogram. The pathological changes of myocardial morphology were observed by htoxylin eosin(HE)and Masson staining. The expressions of type Ⅰ and Ⅲ collagen in myocardial tissue of each group was detected by immunohistochemistry. The mRNA expression levels of IL-10, IL-6 and TNF-<italic>α</italic> in myocardial tissue of each group were detected by quantitative real-time fluorescence polymerase chain reaction(Real-time PCR). The protein expression levels of TGF-<italic>β</italic>₁, <italic>α</italic>-smooth muscle actin(<italic>α</italic>-SMA), Smad2, Smad3 and Smad7 in myocardial tissue of each group were detected by Western blot. <b>Result::Compared with the normal control group, the blood pressure was increased in the model group at 8-15 weeks, LVESD, LVEDD were increased in the model group, while LVFS, LVEF were decreased in the model group. The collagen volume fraction was increased, immunohistochemistry showed the expression levels of type Ⅰ and Ⅲ collagen were increased, mRNA expression levels of IL-10, IL-6 and TNF-<italic>α</italic> were increased, the protein expression levels of TGF-<italic>β</italic>₁, Smad2, Smad3 and <italic>α</italic>-SMA were increased, whereas the protein expression of Smad7 was decreased (<italic>P</italic><0.01). Compared with the model group, the blood pressure rise of each group of Guizhitang was delayed in 12-15 weeks, LVESD and LVEDD were decreased in Guizhitang group (<italic>P</italic><0.01), LVFS, LVEF were increased in Guizhitang group (<italic>P</italic><0.01), the collagen volume fraction was decreased in Guizhitang group (<italic>P</italic><0.01), and the expressions of type Ⅰ and Ⅲ collagen were decreased in Guizhitang group (<italic>P</italic><0.01). At the same time, the mRNA expression of IL-10 was increased in Guizhitang group (<italic>P</italic><0.05, <italic>P</italic><0.01), the mRNA expressions of IL-6 and TNF-<italic>α</italic> were decreased in Guizhitang group (<italic>P</italic><0.01), and the protein expressions of TGF-<italic>β</italic>₁, Smad2, Smad3 and <italic>α</italic>-SMA were decreased in Guizhitang group (<italic>P</italic><0.05, <italic>P</italic><0.01), and the protein expression of Smad7 was increased in Guizhitang group (<italic>P</italic><0.01). Compared with the 2∶1 Guishao group, the effect of the 1∶1 Guishao group in improving the above indicators was more obvious (<italic>P</italic><0.05, <italic>P</italic><0.01). <b>Conclusion::Guizhitang with different proportions of Ramulus Cinnamomi and Poeny can alleviate the degree of myocardial fibrosis in salt-sensitive hypertensive rats. The mechanism may be related to the regulation of TGF-<italic>β</italic>₁/Smads signaling pathway and the reduction of inflammatory response. Besides, the 1∶1 Guishao group showed the optimal effect in reducing inflammation and improving myocardial fibrosis.

m-Nisodipine inhibited 5-HT-induced proliferation of rat PASMCs through Rho/ROCK signal pathway / 药学学报

This paper is to report the exploration of the activation of Rho/ROCK signal pathway in 5-HT-induced proliferation of rat pulmonary artery smooth muscle cells (PASMCs) and the inhibitory effect of m-Nis on this pathway. PASMCs were cultured with the explant technique. MTT assay was used to explore the proliferation of PASMCs after 5-HT treated for different time and the intervening effect of m-Nis. RT-PCR and Western blot were used respectively to explore the mRNA expression of RhoA, ROCK1 and the protein expression of p-MYPT1 in 5-HT-treated PASMCs and intervening effect of m-Nis. The results of MTT assay suggested that 5-HT (1 µmol · L(-1)) treatment for 12-72 h significantly induced the proliferation of rat PASMCs (P<0.05 or P < 0.01), which were inhibited by m-Nis (1 x 10(-5), 1 x 10(-6), l x 10(-7), 1 x10(-8) mol · L(-1)) in dose-dependent manners (P < 0.05 or P < 0.01). Similarly, the mRNA expression of RhoA, ROCK1 and the protein expression of p-MYPT1 were also inhibited by m-Nis in different degrees (P < 0.05 or P < 0.01). Thus, the results of this study suggested that Rho/ROCK pathway played an important role in 5-HT-induced proliferation of rat PASMCs, m-Nis inhibited 5-HT-induced proliferation obviously, which may be related to the blockage of Rho/ROCK signal pathway.

Effect of m-nisoldipine on the Ca2+/CaM/CaN signal pathway in 5-HT-induced proliferation of rat PASMCs / 药学学报

This study is to explore the activation of the Ca2+/CaM/CaN signal pathway in 5-HT-induced proliferation of rat pulmonary artery smooth muscle cells (PASMCs) and the inhibitory effect of m-nisoldipine (m-Nis) on this pathway. PASMCs were cultured with the explant technique. The proliferation of PASMCs was evaluated by MTT assay. Confocal microscopy was used to measure the change of [Ca2+]i. The mRNA expression of CaM and CaN was evaluated by RT-PCR and the activity of CaN was measured according to the instruction of kits. The results of MTT assay suggested that 5-HT (1 micromol x L(-1)) significantly induced the proliferation of rat PASMCs (P < 0.01), which was inhibited obviously by m-Nis (P < 0.05 or P < 0.01). Similarly, m-Nis inhibited 5-HT-induced elevation of [Ca2+]i (P < 0.01). The mRNA expression of CaM, CaN and the activation of CaN were also inhibited by m-Nis at different degrees (P < 0.05 or P < 0.01). Thus, the results of this study suggested that Ca2+/CaM/CaN signal pathway played an important role in 5-HT-induced proliferation of rat PASMCs, the inhibition of m-Nis on proliferation of rat PASMCs may be related to the blockage of Ca2+/CaM/CaN signal pathway by inhibiting the elevation of [Ca2+]i.

m-Nisoldipine attenuates monocrotaline-induced pulmonary hypertension by suppressing 5-HT/ERK MAPK pathway / 药学学报

Effect of new calcium antagonist m-nisoldipine (m-Nis) on MCT-induced PH in rats and its mechanisms were investigated. Rats were injected with a single dose (60 mg x kg(-1)) of MCT subcutaneously to induce PH. Pulmonary haemodynamic measurement and lung tissue morphological investigations were undertaken. The MDA production and SOD activity in the serum were tested. PCNA, ERK1 and p-ERK expressions were analyzed by Western blotting. The expressions of 5-HT and PCNA were observed with immunohistochemistry. Results suggested that the PAP, right ventricular index and the degree of muscularization of small pulmonary artery were elevated markedly in MCT group, which was attenuated by m-Nis treatment. A significant reduction in MDA production and an increase in the SOD activity in the serum were also observed in all three m-Nis groups. The number of PCNA and 5-HT positive smooth muscle cells increased significantly in MCT group, and m-Nis treatment attenuated the expression obviously. Western blotting results suggested that the protein expression of PCNA and the ratio of p-ERK/ ERK1 increased markedly in MCT group and decreased by m-Nis. In conclusion, m-Nis protected against MCT-induced PH by decreasing PAP, right ventricular index, PAMSCs proliferation and pulmonary artery remodelling, which may be related to the reduction of 5-HT and the suppression of the ERK/MAPK signal pathway.

Effects of strophanthidin on intracellular calcium concentration in ventricular myocytes of guinea pig / 药学学报

Effect of strophanthidin (Str) on intracellular calcium concentration ([Ca2+]i) was investigated on isolated ventricular myocytes of guinea pig. Single ventricular myocytes were obtained by enzymatic dissociation technique. Fluorescent signal of [Ca2+]i was detected with confocal microscopy after incubation of cardiomycytes in Tyrode' s solution with Fluo3-AM. The result showed that Str increased [Ca2+]i in a concentration-dependent manner. The ventricular myocytes began to round-up into a contracture state once the peak level of [Ca2+]i was achieved in the presence of Str (10 micromol L(- 1)), but remained no change in the presence of Str (1 and 100 nmol L(-1)). Tetrodotoxin (TTX), nisodipine, and high concentration of extracellular Ca2+ changed the response of cardiomycytes to Str (1 and 100 nmol L(-1)) , but had no obvious effects on the action of Str (10 micromol L(-1)). The elevation of [Ca2+]i caused by Str at all of the detected concentrations was partially antagonized by rynodine (10 micromol L(-1)) or the removal of Ca2+ from Tyrode's solution. In Na+, K+ -free Tyrode' s solution, the response of cardiomycytes in [Ca2+]i elevation to Str (10 micromol L(-1)) was attenuated, while remained no change to Str (1 and 100 nmol L(-1)). TTX, nisodipine, and high concentration of extracellular Ca2+ changed the response of cardiomycytes to Str at all of the detected concentrations in Na+, K+ -free Tyrode's solution. The study suggests that the elevation of [Ca2+]i by Str at the low (nomomolar) concentrations is partially mediated by the extracellular calcium influx through Ca2+ channel or a "slip mode conductance" of TTX sensitive Na+ channel. While the effect of Str at high (micromolar) concentrations was mainly due to the inhibition of Na+, K+ -ATPase. Directly triggering the release of intracellular Ca2+ from sarcoplasmic reticulum (SR) by Str may be also involved in the mechanism of [Ca2+]i elevation.

Transmural L-type calcium current in a pressure-overloaded mouse model with heart failure / 生理学报

Transmural electrical heterogeneity plays an important role in the normal dispersion of repolarizaion and propagation of excitation in the heart. The amplification of transmural electrical heterogeneity contributes to the genesis of arrhythmias in cardiac hypertrophy and failure. We established a mouse model with cardiac failure by aortic banding and investigated the possible contribution of L-type calcium current (I(Ca-L)) to transmural electrical heterogeneity in both normal and failing hearts. Single myocytes were enzymatically isolated from subendocardial and subepicardial myocardium of the free left ventricle wall. The recordings of action potential and I(Ca-L) were performed using the conventional whole-cell patch-clamp technique. The results showed that: (1) The action potential duration at 90% repolarization (APD(90)) of the subendocardial myocytes in normal control mice was (38.2 +/- 6.44) ms, which was significantly longer than that of the subepicardial myocytes [(15.672 +/- 5.31) ms]. The ratio of APD(90) for subendocardial/subepicardial myocytes was about 2.5:1. The peak I(Ca-L) density in subendocardial myocytes was (-2.7 +/- 0.49) pA/pF, which was not different from that in subepicardial myocytes [(-2.54 +/- 0.53) pA/pF]. (2) In failing hearts, both action potential duration at 50% repolarization (APD(50)) and APD(90) were remarkably prolonged either in subendocardial or subepicardial myocytes compared to that in sham hearts. The subendocardial myocytes had much longer APD. The ratio of APD(90) for subendocardial/subepicardial myocytes changed to about 4.2:1. (3) I(Ca-L) density in subendocardial myocytes was significantly decreased in failing hearts compared with that in sham hearts. At four test potentials from +10 mV to +40 mV, the density of I(Ca-L) from subendocardial myocytes in failing hearts was decreased by 20.2%, 21.4%, 21.6% and 25.7%, respectively (P<0.01). However, no significant difference was observed in I(Ca-L) density from subepicardial myocytes in failing hearts. There was no significant difference in the kinetic properties of I(Ca-L) in subendocardial and subepicardial myocytes between the band and sham groups. We conclude that I(Ca-L) may not contribute to the physiological transmural electrical heterogeneity in mouse hearts. The electrical heterogeneity is exaggerated and the density of I(Ca-L) is decreased in the subendocardial myocytes, but not in the subepicardial myocytes in failing hearts. The results obtained suggest that the decreased density of I(Ca-L) in subendocardial myocytes is possibly an adaptive response to the prolongation of action potential due to delayed depolarization and may reduce the transmural dispersion of repolarization in heart failure.

Involvement of nuclear factor of activated T-cells (NFATc) in calcineurin-mediated ischemic brain damage in vivo / 药学学报

<p><b>AIM</b>To study the involvements of nuclear factor of activated T-cells (NFATc) and NF-kappaB in calcineurin-mediated ischemic brain damage in vivo.</p><p><b>METHODS</b>The rat transient forebrain ischemia conducted through 15 min ischemia followed by 8, 24, and 72 h reperfusion was induced using the four-vessel method. The rats were divided randomly into five groups; sham control group, ischemia/reperfusion (I/R) group, CsA treated groups (for 8, 24, and 72 h reperfusion). Western blotting was performed to detect changes of FasL, NFATc, I-kappaB-alpha, and phospho-I-kappaB-alpha protein expression, and gel shift assays for NFAT FasL-DNA binding activities.</p><p><b>RESULTS</b>Western blotting showed that the expressions of both FasL and NFATc protein were significantly increased in the hippocampus of rat subjected to transient forebrain ischemia in comparison with those of the sham control group, which were markedly reduced by CsA. The I-kappaB-alpha protein showed no changes in all groups, and phospho-I-kappaB-alpha protein was not observed in this study. Proximal and distal FasL promoter NFAT sites bind NFAT proteins from the hippocampal neurons subjected to transient forebrain ischemia, and DNA-binding activities increased significantly compared with those of the sham control group. CsA markedly inhibited these changes.</p><p><b>CONCLUSION</b>NFATc may be involved in calcineurin-mediated ischemic brain damage and transcription factor NF-kappaB may not be involved.</p>