Influence of caveolin-1 on the ET-1-induced VSMC proliferation

AIM: To investigate the effect of caveolin-1 on the endothelin-1 (ET-1)-induced vascular smooth muscle cells (VSMC) proliferation. METHODS: The [³H]-thymidine ([³H]TdR) incorporation, immunofluorescence assays and western blotting were used in this study. RESULTS:The ETA receptor specific antagonist BQ123 inhibited the increase in[³H]TdR incorporation in response to ET-1 on VSMC.Immunofluorescence assays showed that caveolin-1 was mostly distributed in plasmalemma of VSMC.After 24 h treatment of VSMC with ET-1,the expression of caveolin-1 in VSMC was significantly decreased.Western blotting showed that ET-1 inhibited the expression of caveolin-1 in VSMC,BQ123 reversed the effect of ET-1.CONCLUSION: Caveolin-1 was mostly distributed in plasmalemma of VSMC. ET-1 downregulated caveolin-1 expression in VSMC via ETA receptor.     

汉沽黑猪和北京黑猪肌肉组织学特性的研究

用冰冻切片测定了汉沽黑猪和北京黑猪背最长肌单位面积内肌纤维所占比例、单根肌纤维横截面积和肌纤维密度,并与大约克夏猪和长白猪做对照。结果：单根肌纤维横截面积,北京黑猪小于长白猪和大约克夏猪（Ｐ＞００５）;汉沽黑猪接近于长白猪和大约克夏猪;肌纤维密度北京黑猪大于长白猪和大约主克夏猪（Ｐ＜００５）,汉沽黑猪小于大约克夏猪而与长白猪相近;单位面积内肌纤维所占比例从大到小依次为长白猪、大约克夏猪、汉沽黑猪和北京黑猪。用剪纸称量法测定了它们肌肉肌纤维、结缔组织和脂肪组织所占面积比。结果表明：肌肉结缔组织所占面积比,汉沽黑猪明显小于大约克夏猪和长白猪,北京黑猪小于大约克夏猪和长白猪;肌纤维所占面积比汉沽黑猪明显大于大约克夏猪（Ｐ＜００１）和长白猪（Ｐ＜００５）,北京黑猪大于大约克夏猪和长白猪（Ｐ＞００５）;肌肉脂肪组织所占面积比四个猪种间结果相近。     

Effects of I.M. injections on serum creatine phosphokinase (CPK) values in dogs

Intramuscular injections of compounds of low irritancy (bicillin, valium, saline) were found to cause significant elevations in serum CPK in dogs. This route of treatment must therefore be avoided in clinical conditions where CPK values have diagnostic or prognostic importance.     

Apoptosis induced by simvastatin in rat vascular smooth muscle cells through calpain and caspase-3-dependent pathways

AIM:Hydroxymethylglutaryl CoA (HMG-CoA) reductase inhibitors, such as simvastatin, have been shown to reduce atherosclerotic cardiovascular morbidity and mortality by mechanisms unrelated to its lipid-lowering effect. Several studies have shown that simvastatin induces apoptosis in a varieties of cell lines including vascular smooth muscle cells (VSMC). The aim of this study was to investigate the signal pathways involved in apoptosis induced by simvastatin.METHODS:Cultured VSMC were treated with simvastatin. Calpain activity was determined by measuring Ca²⁺ ionophore-specific calpain substrate (suc-LLVY-AMC), caspase-3 activation was detected by Western blot, and apoptotic changes were distinguished by annexin Ⅴ binding and DNA laddering.RESULTS:After incubated with 30 μmol/L simvastatin for 8 h, calpain activity had a marked increase (P<0.05, n=4) and reached to more than 3-fold of control at 12 h (P＜0.01). Caspase-3 also activated by simvastatin after 12 h. PD150606, a cell-permeable selective calpain inhibitor, decreased simvastatin-induced apoptosis rate from 24.2%±1.7% to 9.5%±1.9% (P＜0.01) and also prevented simvastatin-induced DNA laddering. Furthermore, 100 μmol/L PD150606 efficiently inhibited simvastatin-induced caspase-3 activation.CONCLUSION:Simvastatin induces apoptosis by activating caspase-3 via calcium-dependent protease calpain.     

The disturbance of calcium metabolism of vascular smooth muscle in the late phase of septic shock and the underlying mechanism

AIM: To evaluate the alterations in calcium metabolism of the vascular smooth muscle in the late phase of septic shock and test the hypothesis that nitric oxide might be involved in sepsis-induced vascular hyporeactivity. METHODS: Male Sprague-Dawley rats were subjected to sepsis by cecal ligation and puncture (CLP). 18 hours post CLP, rat aortic rings were employed for measurement of contractile responses by using organ bath technique. RESULTS: In endothelium-denuded aortic rings from CLP rats, concentration-contraction curves to phenylephrine (PE) and KCl were significantly decreased when compared to that from sham control rats. The transient contraction induced by PE in calcium-free Krebs solution and the concentration-dependent contraction to CaCl₂ in KCl-depolarized medium were also markedly reduced. The hyporeactivity was partially reversed by treatment with aminoguanidine, a selective inducible nitric oxide synthase inhibitor. CONCLUSION: An impairment in calcium handling in vascular smooth muscle is involved in the vascular hyporeactivity during the late phase of septic shock, in which an excessive nitric oxide production might be the major mechanism.     

The effects of short-term recombinant bovine somatotropin treatment on fattening performance,carcass composition and visceral organ weights in karayaka lambs in Turkey

Recombinant bovine somatotropin (bST) was administered s.c. to lambs for 6 weeks to evaluate its effects on fattening performance, carcass composition and visceral organ weights. Twenty male Karayaka lambs were injected with 250 mg bST every two weeks. Body weight, live weight gain, feed intake and feed conversion rate were not affected by treatment. Head, feet, skin, liver, spleen, kidneys, filled and empty gastrointestinal tract, penis, testis, pelvic fat and internal fat weights were similar for the two groups. Lung weight increased by 17.4% (P < 0.01) and weight of heart decreased 22.7% (P < 0.05) in bST treated lambs. The only carcass characteristics that were affected by bST administration were limb muscle which increased from 1331 g to 1417 g (P < 0.05), loin fat which decreased from 275 g to 174 g (P < 0.01), shoulder fat which decreased from 26 g to 13 g (P < 0.01) and total fat/final weight percentage which decreased from 9.8% to 7.6% (P < 0.05). The results of this study show that prolonged release formulation of bST treatment reduces fat tissue, but does not significantly affect fattening performance or weights of visceral organs, muscle and bone.     

神经肌亚体内肌纤维型的生后发育

将生后2天、2周、4周、8周、12周、16周、20周、24周的家兔胫骨前肌分成前、后亚体,分别得到腓得神经主要肌分支的支配,腓深神经分支的神经分布型式随年龄增长而递降.每个肌亚体组织化学特征经由乙酰胆碱碘溶液孵育后的运动终板而确定.肌纤维可分成SO、FG、FOG和FO型.除外生后2天龄之外,前、后亚体内SO、FG、FOG肌纤维在生后2周龄、4周龄、8周龄分别约占30%左右,生后12周龄以后,在前亚体内的SO型与FOG型纤维比率下降和FG型纤维升高要超过后亚体.全部肌纤维型在生后2周龄、4周龄、8周龄、12周龄的每个肌亚体的深、中、浅部都是均匀性分布.然而,不同部位的肌纤维类型差别明显,深部以氧化型为主,而浅部则以糖酵解型为主.这种差别在生后16、20、24周龄是最典型的.两个亚体生后发育期间的每条肌纤维毛细血管数(NCF)表明SO>FO>FOG>FG型纤维和毛细血管数与肌纤维横切面积比(CCA)显示FO>SO>FOG>FG型纤维,由此指出氧供较大需求的获得是通过减小肌纤维的面积而不仅仅是依赖于增加毛细血管数量.     

Role of angiotensin Ⅱ in the regulation of platelet-derived growth factor receptor β subunit of vascular smooth muscle

AIM:To investigate the crosstalk between angiotensin Ⅱ (AngⅡ)-mediated and platelet-derived growth factor (PDGF)-mediated signal transduction in vascular smooth muscle proliferation.METHODS:A model of renal hypertension was made by two kidney/one-clip operation. Level of PDGF receptor β subunit of aorta was measured by Western Blot analysis. The effect of Ang Ⅱ on PDGF receptor β subunit expression was investigated in culture rat aortic vascular smooth muscle cells (VSMC).RESULTS:Systolic blood pressure obviously increased at 8th week after operation, whereas the level of PDGF receptor β subunit of aorta significantly increased by 126.6% (P＜0.05) in 2K1C rats compared with control group. The expression of PDGF receptor β subunit in cultured VSMC stimulated by AngⅡ was higher than that of control by 192.74%(P＜0.01). The effect of AngⅡ was inhibited remarkably by pretreated with losartan, a kind of specific AngⅡ receptor 1 (AT₁) subtype antagonist and U73122, a kind of phospholipase C inhibitor. The effect was partly blocked by PD98059, which inhibit the activity of mitogen-activated, ERK-activating kinase (MEK).CONCLUSION:AngⅡ-induced PDGF receptor β subunit expression is regulated by the AT₁ and its downstream signal molecule-PLC and ERK, might participate in the intracellular signal transduction pathway.