Roles of PIK3R1 gene in development of hepatocellular carcinoma / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the roles of phosphatidylinositol 3 kinase regulatory subunit alpha (PIK3R1）gene in the development of hepatocellular carcinoma （HCC）.</p><p><b>METHODS</b>Surgical specimens of liver cancer and corresponding pericancerous liver tissue were collected from 20 patients with hepatocellular carcinoma. Expression of p85α, encoded by PIK3R1, in HCC tissue specimens was detected by Western blotting and immunohistochemistry. HCC HepG2 cells were transfected with PIK3R1 siRNA or PIK3R1-cDNA. The expression of PIK3R1 in transfected HepG2 cells or control cells were detected by real-time PCR. Cell proliferation was evaluated by MTT, colony formation assays and flow cytometry respectively. The expression of PI3K/AKT pathway-related proteins were detected by Western blotting.</p><p><b>RESULTS</b>The expression of p85α in liver tissue was higher than that in pericancerous tissues (1.27±0.58 vs 0.99±0.47，t=-3.25，P<0.05）. The expression of PIK3R1 was decreased by 0.19±0.03 fold in PIK3R1siRNA-transfected HepG2 cells(t=46.77，P<0.05)，and increased by 32.36±3.33 fold in PIK3R1 cDNA -transfected cells（t=-16.31， P<0.05）. MTT result showed that PIK3R1 siRNA inhibited growth of HepG2 cells （0.611±0.072 vs 0.807±0.059，t=3.65，P<0.05），while PIK3R1 cDNA increased the cell growth（0.937±0.060 vs 0.693±0.065，t=-4.78，P<0.05）. PIK3R1 siRNA transfected cells presented lower colony-forming efficiency than control group（3.8%±0.84% vs 15.0%±2.3%，t=7.92，P<0.05），while PIK3R1 cDNA transfected cells had higher colony-forming efficiency than control group (23.6%±3.4% vs 12.0%±1.5%，t=-5.40，P<0.05）. PIK3R1 siRNA reduced the ratio of S phase cells（13.9%±0.015% vs 32.9%±0.07%，t=45.97，P<0.01, while PIK3R1 cDNA increased S phase cells（56.33%±0.024% vs 31.94%±0.042%，t=-8.73，P<0.01）. PIK3R1 increased the level of p-AKT and decreased p53 level. CONCLUSION：p85α is highly expressed in HCC，and PIK3R1 gene may promote proliferation of HepG2 cells by activating PI3K/AKT pathway.</p>

Effect of AT₁ receptor on changes of tyrosine hydroxylase-immunoreactivity in rostral ventrolateral medulla induced by brain cholinergic stimuli in rats / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of AT₁ receptor on the changes of tyrosine hydroxylase-immunoreactivity (TH-IR) in rostral ventrolateral medulla (RVLM) induced by brain cholinergic stimuli in rats.</p><p><b>METHODS</b>Male SD rats were randomly divided into 4 groups: NS + CBC group, Los + CBC group, Los + NS group and NS + NS group. AT₁ was blocked by pretreatment of 20 μg losartan in Los + CBC and Los + NS groups; intracerebroventricular injection of 0.5 μg carbachol was used for cholinergic stimuli in NS + CBC and Los + CBC groups; normal saline (NS) was used for control. The output amount of natrium in kidney, glomerular filtration rate (GFR) and renal plasma flow (PRF) were observed. The changes of TH-IR in the RVLM were observed by immunohistochemistry.</p><p><b>RESULT</b>In NS + CBC group carbachol induced potent natriuresis, after pretreatment of losartan the natriuretic effect was partially inhibited in Los + CBC group. Both the number and optical density of TH-IR positive neurons in NS + CBC group were markedly increased than those in NS + NS group (P < 0.05); while those in Los + CBC group were significantly lower than those in NS+CBC group (P < 0.05). Intracerebroventricular injection of carbachol and losartan had no effect on GFR and RPF(P > 0.05).</p><p><b>CONCLUSION</b>The results suggest that cholinergic stimuli can induce potent natriuresis and increase the activity of adrenergic neurons in the RVLM; the above effects can be down regulated by blockade of brain AT₁ receptor.</p>

Effect of nitric oxide synthase inhibitors on the changes of hemodynamic parameters and aortic tension induced by septic shock in rats / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effect of three types of nitric oxide synthase inhibitors on the changes of hemodynamic parameters and thoracic aorta tension induced by septic shock in rats.</p><p><b>METHODS</b>We used cecal ligation and puncture (CLP) method to establish septic shock in rats, and the three types of nitric oxide synthase inhibitors were injected after CLP. The carotid artery was cannulated and connected to a pressure transducer to determine mean arterial blood pressure (MABP). Ventricular dynamic parameters were determined following intraventricular cannulation via the carotid artery, including heart rate (HR), left ventricular developed pressure (LVDP), maximal rise/fall velocity of ventricular pressure (+/- dP/dt(max)). Isolated thoracic rings were mounted on an organ bath and the tension of the vessel was recorded.</p><p><b>RESULTS</b>(1) After using L-NAME, AMG and 7-NI the mortality decreased to 50.0%, 37.5%, and 42.1%, respectively (from 65.2% in septic shock rats); (2) The MABP in septic shock rats partly recovered after using the NOS inhibitors, all ventricular dynamic parameters partly recovered after using the inhibitors; (3) The hyporeactivity of endothelium-denuded aortic rings to vasoconstrictors induced by septic shock was partly recovered by pretreatment with the inhibitors. However, only L-NAME or 7-NI could inhibit the decrease of vasoconstriction induced by septic shock in endothelium-intact aortic rings.</p><p><b>CONCLUSION</b>The three types of nitric oxide synthase inhibitors can improve the hemodynamic parameters and vasoconstriction responsiveness of endothelium-denuded aorta of septic shock rats. Furthermore, L-NAME and 7-NI improve the responsiveness of endothelium-intact aorta.</p>

Vascular effect of extract from mulberry leaves and underlying mechanism / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the vascular activity of extract from mulberry leaves (EML) on rat thoracic aorta and the underlying mechanism.</p><p><b>METHODS</b>Isolated thoracic rings of Sprague-Dawley rats were mounted on the organ bath and the tension of the vessel was recorded.</p><p><b>RESULT</b>(1) EML produced a concentration-dependent vasorelaxation of aorta preconstricted by high K(+) (60 mmol/L) or 10(-6) mol/L phenylephrine (PE) in endothelium-intact and endothelium-denuded arteries. (2) EML at EC(50) concentration reduced the calcium dose-response curve. (3) After incubation of aorta with verapamil, EML induced vasocontraction of aorta preconstricted by PE, which was abolished by ruthenium red.</p><p><b>CONCLUSION</b>The vascular effect of EML is biphasic, the vasorelaxation is greater than the vasocontraction. The vasorelaxation induced by EML may be mediated by inhibition of voltage-and receptor-dependent calcium channels in vascular smooth muscle cells, while the vasocontraction is via activation of ryanodine receptor in endoplasmic reticulum.</p>

The alterations of nitric oxide synthase activity of ventricular cardiac muscle of rats in two septic shock models / 中国应用生理学杂志

<p><b>AIM</b>To observe the differences of hemodynamics and nitric oxide synthase(NOS) activity of ventricular cardiac muscle in two septic shock models and explore the possible mechanism.</p><p><b>METHODS</b>Two rat models of septic shock[lipopolysaccharide(LPS)-induced and cecal ligation and puncture (CLP)-induced septic shock] were used. The hemodynamic parameters and nitric oxide synthase activity of ventricular cardiac muscle were measured.</p><p><b>RESULTS</b>The hemodynamic parameters in CLP-induced model were increased in the early stage and decreased in the late stage while in LPS-induced model the parameters showed the same change of the CLP late stage. Both LPS model and CLP model (late stage) showed significant increase in NOS activity, but there was no difference between the two models. After treatment of the NOS inhibitor N-nitro-L-arginine methyl ester (L-NAME), the parameters of CLP-late stage and LPS model increased significantly. The NOS activity reached the highest level in the CLP-middle stage. The production of nitrite/nitrate decreased significantly in LPS model and CLP model(late stage) after treatment of L-NAME, but the nitrite/nitrate produced by constitutive NOS in LPS model was higher than CLP model(late stage).</p><p><b>CONCLUSION</b>The increase of the NOS activity may be the main reason to lead to the depression of the hemodynamic parameters. Inducible NOS may play the leading role in the LPS model while cNOS and iNOS have the same effect in the CLP model.</p>

Comparison of vasodilatation effect between quercetin and rutin in the isolated rat thoracic aorta / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To determine the possible difference in vasodialtation effect of quercetin and rutin.</p><p><b>METHODS</b>The isolated rat thoracic aorta was treated with phenylephrine (PE), and the effects of quercetin and rutin on the preconstricted aorta rings with or without endothelium were determined by organ bath technique. Nitric oxide synthase inhibitor L-N(G)-nitroarginine methyl-ester (L-NAME), guanylyl cyclase inhibitor methylene blue, cyclooxygenase inhibitor indomethacin were used to explore the mechanism.</p><p><b>RESULTS</b>Quercetin (10-160 micromol/L) caused vasorelaxation of aorta rings preconstricted with PE in endothelium-intact and denuded aorta rings in a dose-dependent manner. Rutin(10-160 micromol/L) caused dose-dependent vasorelaxation in endothelium-intact rings preconstricted with phenylephrine, but not in denuded aorta rings. The maximal response (Rmax) values calculated from vasorelaxation curves of quercetin and rutin were (77.20+/-6.11)% and (44.28+/-7.48)%, respectively. There was no difference between median effective concentration (EC(50)) values of quercetin and rutin. Pretreatment with L-NAME (0.1 mmol/L) abolished the vasorelaxation by rutin,but did not influence the vasodilating effect of quercetin in endothelium-intact rings. Pretreatment with methylene blue (10 mmol/L) canceled the vasorelaxation both by quercetin and rutin. Pretreatment with indomethacin (10 micromol/L) attenuated the vasodilatation of quercetin, but did not affect the vascular effect of rutin.</p><p><b>CONCLUSION</b>The vasodilatation effect of quercetin is more potent than rutin. The vasodilatation effect of quercetin might be mediated by guanylyl cyclase and cyclooxygenase-dependent pathway, while the vasodilatation by rutin might be via nitric oxide-guanylyl cyclase pathway.</p>