Effects of retinal ganglion cell apoptosis on delayed rectifier K+ currents

AIM: To investigate the effects of rat retinal ganglion cell (RGC) apoptosis on delayed rectifier K⁺ currents (I_K). METHODS: The retinas of 2~3 d newborn Sprague-Dawley rats were dissociated into cell suspension by trypsin digestion. The RGCs were cultured and divided into control group, pressure 0.5 h group, pressure 1 h group, pressure 1.5 h group and pressure 2 h group. The cells were cultured regularly for 6 d in control group, and the cells in other groups were cultured regularly for 6 d and gave pressure of 80 mmHg for 0.5 h, 1 h, 1.5 h and 2 h, respectively. The rhodamine 123 fluorescence from labeled RGC mitochondrion was detected by continuous wavelength multifunctional microplate detection instrument. The membrane capacitance (C_m) in different groups and I_K in the pressure 1 h group were recorded from the RGCs by whole-cell patch-clamp technique. RESULTS: No difference of rhodamine 123 fluorescence in the RGC mitochondria between control group and pressure 0.5 h group was observed. Rhodamine 123 fluorescence in the other 3 groups was significantly lower than that in control group (P<0.05). No difference of the C_m between control group and pressure 0.5 h group was found, and the C_m in the other 3 groups was significantly lower than that in control group (P<0.05). The amplitudes of I_K were higher than that in control group. At the test potential from -10 mV to 60 mV, the current density in pressure 1 h group was significantly higher than that in control group (P<0.05). The maximal conduction (G_max) in pressure 1 h group was significantly higher than that in control group. The voltage for I_K channel half-activation (V_1/2) in pressure 1 h group declined comparison with control group (P<0.01), and the k value had no significant difference between the 2 groups. CONCLUSION: Retinal ganglion cell apoptosis accompanies with delayed rectifier K⁺ current enhancement.     

Changes of potassium currents in rabbit ventricle with healed myocardial infarction

AIM: To elucidate the mechanism of arrhythmia in healed myocardial infarction (HMI), and to investigate the changes of action potential duration (APD),transient outward potassium current (I_to), delayed rectifier potassium current (I_K) and inward rectifier potassium current (I_K1) of left ventricular myocytes in noninfarcted zone of HMI. METHODS: 12 rabbits were randomly assigned in two groups: HMI group (thoracotomy and ligation of the circumflex coronary); sham-operated group (thoracotomy but no conorary ligation). 3 months after operation, whole cell patch clamp technique was used to record APD, I_to, I_K and I_K1 of ventricular myocytes in non-infarcted zone. RESULTS: Membrane capacitance was larger in HMI group than that in sham-operated group. Action potential duration was lengthened significantly in HMI group and early after depolarization (EAD) appeared in HMI group. The densities of I_to, I_K,tail and I_K1 were reduced significantly in HMI group (P<0.01), from (6.72±0.42) pA/pF, (1.54±0.13) pA/pF and (25.6±2.6) pA/pF in Sham-operated group to (4.03±0.33) pA/pF, (1.14±0.11) pA/pF and (17.6±2.3) pA/pF, respectively. CONCLUSION: The reduced densities of I_to, I_K,tail and I_K1 in ventricular myocytes of non-infarcted zone in HMI are responsible for the prolongation of APD and the presentation of EAD, which play important roles in the malignant arrhythmia of HMI.     

Roles of PI3K/Akt and JAK2/STAT3 signaling pathways in protection of SO2 against limb ischemia/reperfusion-induced acute lung injury in rats

AIM: To investigate the role of PI3K/Akt and JAK2/STAT3 pathways in the protection of sulfur dioxide (SO₂) against limb ischemia/reperfusion (I/R)-induced acute lung injury (ALI) in rats. METHODS: ALI was induced by limb I/R in the SD rats. Na₂SO₃(0.54 mmol/kg, ip)/NaHSO₃ (0.18 mmol/kg, ip) as SO₂ donor was injected at 20 min before reperfusion. The inhibitors of JAK2/STAT3 and PI3K/Akt pathways, Stattic (3 mg/kg, iv) and LY294002(40 mg/kg, iv), respectively, were injected at 1 h before reperfusion. Peripheral blood and lung tissues were collected for determining the contents of the cytokines, the protein levels of the molecules related to the signaling pathways, apoptosis and histopathologic changes by ELISA, TUNEL and Western blot. RESULTS: Compared with control group, the content of MDA, the activity of MPO, lung coefficient, apoptotic index, cytokine expression, and the protein levels of p-Akt and p-STAT3 in I/R group all increased significantly, and administration of Na₂SO₃/NaHSO₃ attenuated the damage in the lung. Besides, the results of Western blot showed that the rat lung tissues expressed p-STAT3 protein and p-Akt protein. After I/R, the protein levels of p-STAT3 and p-Akt were increased. After using Na₂SO₃/NaHSO₃, p-Akt was increased, but p-STAT3 was decreased (P<0.05). CONCLUSION: Both JAK2/STAT3 and PI3K/Akt pathways are likely involved in the protective effect of SO₂ against limb I/R-induced ALI in rats. The activation of JAK2/STAT3 signaling pathway increases I/R injury. Reversely, the activation of PI3K/Akt signaling pathway reduces I/R injury. Besides, JAK2/STAT3 and PI3K/Akt signaling pathways may have crosstalk during I/R-induced ALI and JAK2/STAT3 pathway may have an impact on the P13K/Akt pathway.     

Effect of salvianolic acid B on high glucose-induced phenotypic transition and extracellular matrix secretion in human glomerular mesangial cells

AIM:To investigate the effect of salvianolic acid B (Sal B) on high glucose-induced phenotypic transition and extracellular matrix (ECM) secretion in human glomerular mesangial cells (HGMCs) and the underlying mechanisms. METHODS:HGMCs were randomly divided into control group, high glucose group and high glucose plus high dose, medium dose and low dose of Sal B groups. The HGMCs except those in control group were exposed to high glucose (33.3 mmol/L) for 72 h, while those in Sal B groups were co-incubated with indicated concentrations of Sal B. The protein levels of α-smooth muscle actin (α-SMA), transforming growth factor-β₁ (TGF-β₁) and phosphorylated Smad2 and p38 mitogen-activated protein kinase (MAPK) were determined by Western blot. The secretion levels of collagen type I (Col I), collagen type Ⅲ (Col Ⅲ), fibronectin (FN) and laminin (LN) were measured by ELISA. RESULTS:Exposure to high glucose markedly increased the protein expression of α-SMA, TGF-β₁, Col I, Col Ⅲ, FN and LN in the HGMCs (P<0.01). The phosphorylation levels of Smad2 and p38 MAPK were also significantly increased (P<0.01). Co-incubation with Sal B evidently decreased the protein expression of α-SMA, TGF-β₁, Col I, Col Ⅲ, FN and LN in the HGMCs induced by high glucose (P<0.05 or P<0.01). The phosphorylated levels of Smad2 and p38 MAPK were also reduced noticeably (P<0.05 or P<0.01). CONCLUSION:Sal B significantly suppresses high glucose-induced phenotypic transition and ECM secretion in the HGMCs, which might be attributed, at least partly, to inhibition of TGF-β₁/Smad signaling pathway and p38 MAPK activation.     

嫁接对高温和低温胁迫下辣椒幼苗快速叶绿素荧光诱导动力学特性的影响

以辣椒材料‘P205’和‘野力姆’为砧木,以‘三道筋’为接穗进行嫁接,研究了嫁接对高温（45 ± 1）℃和低温（4 ± 1）℃胁迫下辣椒快速叶绿素荧光诱导动力学特性的影响。结果表明：温度胁迫引起自根苗叶片快速叶绿素荧光诱导曲线（OJIP）发生显著变化,J、I、P相降低明显。JIP-test分析显示,荧光诱导曲线中出现了明显K相,且自根苗和嫁接苗在高温胁迫后的ΔK值均高于低温胁迫,说明辣椒叶片光合机构更易受到高温胁迫的损伤。温度胁迫降低了自根苗和嫁接苗的最大光化学效率（F_v/F_m）、性能指数（PI_abs）,其中PI_abs对温度胁迫更敏感。自根苗和嫁接苗叶片的反应中心单位面积上吸收（ABS/CS_m）、捕获（TR_o/CS_m）和传递（ET_o/CS_m）的光能以及反应中心数量（RC/CS_m）在温度逆境中下降,而J相相对可变荧光（V_J）、热耗散量子比率（Ψ_Do）、单位面积的热耗散（DI_o/CS_m）和综合性能指数（PI_total）升高,其中自根苗所有荧光参数值均与常温对照差异显著。砧木‘P205’嫁接苗和砧木‘野力姆’嫁接苗分别对高温和低温胁迫具有较好的适应性。自根苗和嫁接苗叶片的PI_total在温度逆境下均大幅升高,胁迫解除后又迅速恢复,表明在温度胁迫下辣椒叶片光系统Ⅰ（PSⅠ）的受损伤程度较PSⅡ低。     

Effects of urocortin-I preconditioning on myocardial mitochondrial respiratory function and enzyme activity in rats

ATM: To investigate the influence of urocortin-I (Ucn I) preconditioning on the myocardial mitochondrial respiratory function and enzyme activity in the rats with ischemia reperfusion, and to observe the changes of ATP content in the myocardial cells. METHODS: (1) The healthy male Sprague-Dawley rats were randomly divided into 4 groups:normal group (Nor group), ischemia reperfusion group (IR group), Ucn I preconditioning group (Ucn I group), 5-hydroxy acid (5-HD)+Ucn I group. Langendorff perfusion was used to establish the in vitro model of cardiac ischemia reperfusion. At the end of the balance (T₁), before ischemia (T₂) and at the end of the reperfusion (T₃) respectively, the myocardial mitochondria was extracted, the mitochondrial respiratory function and respiratory enzyme activity in each group were determined. (2) The method of MPA isolated heart perfusion was used to isolate myocardial cells of the adult rats. After cultured for 24 h, myocardial cells were divided into 4 groups:Nor group, hypoxia/reoxygenation group (I/R group), Ucn I group, 5-HD+Ucn I group. Hypoxia/reoxygenation model of myocardial cells was established. At the end of reoxygenation, the changes of myocardial ATP content were measured by high performance liquid chromatography.RESULTS: (1) Compared with T₁, T₂ time points, the respiratory function (state 3 respiratory rate, respiratory control rate) and NADH oxidase, succinate oxidase and cytochrome C oxidase activities at T₃ time point were significantly decreased (P<0.05) in all groups except Nor group. At T₃ time point, the myocardial mitochondrial respiratory function and respiratory enzyme activity in Ucn I group were superior to 5-HD+Ucn I group and IR group (P<0.05), but was inferior to Nor group (P<0.05). At T₃ time point, the respiratory function of myocardial mitochondria and respiratory enzyme activities (NADH oxidase, succinate oxidase) in 5-HD+Ucn I group were better than those in IR group (P<0.05), but no statistical difference of the cytochrome C oxidase activity between the 2 groups was observed. The respiratory function and 3 kinds of respiratory enzyme activities at T₁, T₂ time points had no statistical change. (2) At the end of the reoxygenation, the myocardial ATP content in Nor group was higher than that in other groups (P<0.01). The myocardial ATP contents in I/R group and 5-HD+Ucn I group were lower than that in Ucn I group (P<0.05). In additon, 5-HD+Ucn I group was higher ATP content compared with I/R group (P<0.05). CONCLUSION: Ucn I preconditioning attenuates the ischemia/reperfusion induced damages of myocardial mitochondrial respiratory function and respiratory enzyme activity, thus ensuring the myocardial ATP contents under the condition of hypoxia/reoxygenation.     

Effect of angiotensin-(1-7) on angiotensin II-induced rat renal interstitial fibroblast activation

AIM: To explore the influence of angiotensin-(1-7) on angiotension II (Ang II)-induced activation and extracellular matrix secretion in rat renal interstitial fibroblasts (NRK-49F cells). METHODS: The NRK-49F cells were maintained and sub-cultured, then the cells were divided into control group, Ang II group, Ang-(1-7) group and Ang II+Ang-(1-7) group. The expression of α-smooth muscle actin(α-SMA),transforming growth factor β₁ (TGF-β₁) and insulin-like growth factor I(IGF-I) was detected by the method of immunocytochemistry when the cells were cultured for 72 h. The content of TGF-β₁, IGF-I and collagen type I(Col I) in the cultured supernatants were measured by ELISA. RESULTS: In control group and Ang-(1-7) group, only basic expression of α-SMA and almost no expression of TGF-β₁, IGF-I and Col I were observed. Compared with control group, the expression of α-SMA, TGF-β₁, IGF-I and Col I was increased in Ang II group. Compared with Ang II group, the expression of α-SMA, TGF-β₁, IGF-I and Col I was significantly decreased in Ang II+Ang-(1-7) group.CONCLUSION: Ang-(1-7) inhibits the activation of renal interstitial fibroblasts and decreases the Ang II induced secretion of Col I by suppressing TGF-β₁ and IGF-I expression.     

Effect of inhaled nitric oxide on the gas exchange and hemodynamic of ischemia-reperfusion lung in rabbit model

AIM:To evaluate the effect of pulmonary gas exchang and hemodynamic by inhaled nitric oxide on ischemia-reperfusion(I/R) lung in rabbit model.METHODS:Forty Newzealand rabbits were divided into four groups: group Ⅰ, sham-operated; group Ⅱ, sham-operated with inhaled nitric oxide (NO); group Ⅲ, I/R; group Ⅳ, I/R with Inhaled NO. Pulmonary artery pressure (PA), pulmonary vascular resistance(PVR), arterial oxygen tension(PaO₂), arterial carbon dioxide tension (PaCO₂), alveolar-arterial gradient (A-aDO₂), Shunt fraction (Qs/Qt) expression of CD₁₈, peripheral leukocyte, methemoglobin were continuetly quantitated. RESULTS:At the start of reperfusion inhaled NO significantly improved PaO₂ and decreased PA, PVR,PaCO₂,A-aDO₂,Qs/Qt.CONCLUSION:Inhaled NO ameliorated significantly the early gas exchange and hemodynamic of reperfusion lung.     

Effect of bFGF on human kidney fibroblasts

AIM: To study the effect of bFGF on cell proliferation, secretion of type I collagen and expression of integrin β₁ in human kidney fibroblasts(KFB). METHODS: The KFB was cultured and stimulated by bFGF in vitro. The proliferation and collagen I secreting of KFB, the expression of integrin β₁ were measured by MTT, ELISA and flow cytometer, respectively. RESULTS: bFGF(25-50 μg/L) could obviously stimulate the cell proliferation(P< 0.05), promote the secretion of collagen I(P< 0.05) and enhance the expression of integrin β₁(P< 0.05) in human kidney fibroblast. CONCLUSION: bFGF could induce renal interstitial fibrosis by promoting cell proliferation, secretion of collagen I and integrin β₁ expression of KFB.     

Effects of simulated ischemia/reperfusion on spontaneous action potentials in primary cultured sinoatrial node cells and the influence of pinacidil

AIM: To study the effects of ischemia/reperfusion (I/R) on primary cultured sinoatrial node (SAN) cells and the influence of pinacidil (a K_ATP channel activator). METHODS: The SAN cells were isolated from newborn rats and purified. The 48 h cultured cells were cultivated in following mediums: simulated reperfusion solution as normal control, simulated ischemia/reperfusion solution (I/R), Pinacidil+I/R (P+I/R), 5-HD+P+I/R and 5-HD+I/R. Spontaneous action potentials were recorded by ruptured-patch whole-cell technique in current clamp (I=0) and the maximum diastolic potential (MDP), upstroke velocity (UV), action potential overshoot (APO), interbeat interval (IBI) and action potential durations at 50% repolarization (APD₅₀) were measured. RESULTS: Compared with control group, simulated ischemia/reperfusion shorten APD₅₀, reduced UV, MDP and APO. Exposed to pinacidil, MDP of cells in I/R groups was hyperpolarized; IBI, UV and APO were increased; APD₅₀ was shorten. 5-HD couldn't block the effects of pinacdil on APD₅₀, IBI and MDP, but reversed its actions on increasing UV and APO. CONCLUSIONS: Pinacidil made changes of AP in I/R group by opening different K_ATP channels of SAN cells. The role of this changes on protection in SAN cells during ischemia/reperfusion requires further investigation.     

Establishment of arsenic trioxide-resistant K562/AS2 cell line and the mechanism of multidrug resistance

AIM:To establish a arsenic trioxide (As₂O₃ )-resistant leukemic cell line to explore the mechanism of resistance to As₂O₃, and the relationship between the resistant cell line and the multidrug resistance was also investigated. METHODS:The arsenic trioxide (As₂O₃ )-resistant leukemic cell line was established by exposing the cells to the increasing concentration of As₂O₃. MTT assay was used to detect the cytotoxicity. Cell cycle was detected by PI assay. Flow Cytometry was used to detect the P-glycoprotein on the surface of the cells, the intracellular concentration of DNR, and the immuetype of the cells. RESULTS:The cell doublings time and the cell cycle of the arsenic trioxide (As₂O₃ )-resistant leukemic cell line, K562/AS2, is similar to that of K562. The relative resistant fold of K562/AS2 to As₂O₃, DNR, VP16 and Ara-C was 7.4, 2.9, 3.8 and 1.1, respectively. The relative resistant fold of multidrug resistant cell line, K562/ A02, to As₂O₃, DNR, VP16 and Ara-C was 0.8、94、2.5 and 0.9, respectively. The fluorescence of the P-glycoprotein on the surface or of the DNR inside the cells detected was not significantly different between the K562 and the K562/AS2 cell lines. CONCLUSIONS:A cell line, K562/AS2, resistant to clinical achieving level (2 μmol/L) of As₂O₃ has been established. The relative resistant fold of K562/ AS2 to As₂O₃ is about 7.4 fold to the parent K562 line sensitive to As₂O₃. Partial resistance of K562/AS2 to DNR and VP16 is observed , the mechanism of which is unrelated to the P-gp, the expression product of multidrug resistance gene 1 (mdr1).     

Reverse effects of saikoside on multidrug resistance of human leukemic cell line K562/ADM in vitro

AIM: To study the reverse effects of saikoside (SS) on the multidrug resistance (MDR) of human leukemic cell line K562/ADM and to investigate the related mechanism. METHODS: K562 cells and K562/ADM cells in the culture were treated with SS at the concentrations of 1~100 mg/L. The inhibitory rate of the cell proliferation was measured by MTT assay. Non-cytotoxic dose of SS was determined. K562/ADM cells were treated with SS at non-cytotoxic doses of 1.25, 2.5 and 5.0 mg/L with different concentrations of adriamycin (ADM,0.05~100 mg/L). The 50% inhibitory concentration (IC₅₀) and the reversal index in all groups were determined. The cell morphology was observed after treated with SS+ADM. The effects of SS on ADM accumulation in K562/ADM cells, the cell cycle profile and apoptosis were examined by flow cytometry. RESULTS: The inhibitory rates were significantly increased in a dose-dependent manner when the cells were treated with different doses of SS (1~100 mg/L). The available reversal concentration of SS was 5.0 mg/L and the reversal index was 21.5 folds for K562/ADM cells. After treated with SS+ADM, the number of tumor cells was decreased and apoptotic cells were increased in a dose-response relationship. ADM accumulation in K562/ADM cells treated with SS was significantly higher than that in control cells (P<0.05). SS may significantly enhanced the apoptosis of K562/ADM cells treated with ADM (P<0.05). K562/ADM cells treated with SS were blocked in the stage of G₀/G₁. CONCLUSION: SS has effect on proliferation inhibition and MDR reversal in K562/ADM cell line. The reversal mechanisms of SS may be due to increasing the accumulation of chemo therapeutics in the cell, inducing the cell apoptosis and arresting the cells in G₀/G₁ phase.     

Effects of PI3K/PKB signaling pathway on expression of osteopontin in human hepatic stellate cells induced by transforming growth factor-β1

AIM: To investigate the regulatory effects of phosphatylinositol 3-kinase/protein kinase B (PI3K/PKB) signaling pathway on the expression of osteopontin (OPN) in transforming growth factor-β₁ (TGF-β₁)-induced human hepatic stellate cells. METHODS: Human hepatic stellate cell line LX-2 was cultured in DMEM and stimulated by TGF-β₁ at the final concentration of 2.5, 5, 10 and 20 μg/L for 24 h or at final concentration of 10 μg/L for 12 h, 24 h and 48 h. LX-2 cells were pretreated with wortmannin, a specific inhibitor of PI3K/PKB signaling pathway, at final concentration of 0.1 μmol/L for 1 h, followed by incubation with TGF-β₁ at final concentration of 10 μg/L for 24 h. The cells were collected. The expression of OPN was detected by real-time PCR and Western blotting. RESULTS: In LX-2 cells, the expression of OPN was apparently elevated when incubated with TGF-β₁. With the increase in TGF-β₁ concentration or the extension of incubation hours, the expression of OPN was increased gradually in a dose-and time-dependent manner with certain limits. LX-2 cells pretreated with wortmannin and incubated with TGF-β₁ had a significant decrease in the OPN expression as compared with control group (P<0.01). CONCLUSION: The expression of OPN in TGF-β₁-induced LX-2 cells is regulated by the PI3K/PKB signaling pathway.     

Storage conditions and ripening of chiku fruits Achras sapota L.

Chiku fruits (Achras sapota L.) were found to be climacteric with the respiratory peak occurring at the same time, or 1–2 days after peak ethylene production. The optimum storage temperature was near 20° C. Storage life at this temperature could be increased by removing ethylene (C₂H₄) and adding 5–10% (v/v) carbon dioxide (CO₂) to the storage atmosphere. Extreme relative humidities or high concentrations of CO₂ impaired the quality of stored fruits. Ripening was not affected by treatment with oxygen, C₂H₄ or indoleacetic acid. Ascorbic acid and glucose levels increased with ripening but ascorbic acid decreased when the fruit became over ripe. Recommended storage conditions are about 20° C with 5–10% CO₂ coupled with the complete removal of C₂H₄ from the storage atmosphere. Short-term holding of the fruit at lower temperatures is also possible.     

Rapid preparation of hypoxic Krebs-Henseleit solution with sodium sulfite for in vitro model of hypoxic pulmonary vasoconstriction

AIM: To investigate the feasibility of using sodium sulfite (Na₂SO₃) to prepare hypoxic Krebs-Henseleit (KH) solution for hypoxic pulmonary vasoconstriction (HPV) model in vitro. METHODS: Different doses of Na₂SO₃ were added into 0.5 L KH solution at 37°C. An i-STAT portable clinical analyzer was used to measure the oxygen partial pressure (PO₂), carbon dioxide partial pressure (PCO₂), pH value and the concentration of sodium (Na⁺) in these KH-Na₂SO₃ solutions 1 min after administration. Then the dose of Na₂SO₃ suitable for HPV model was dissolved in 0.5 L KH solution and the above indexes in the solution were monitored at various time points at 37°C under atmospheric pressure. RESULTS: More than 0.2 g (including 0.2 g) Na₂SO₃ reduced the PO₂ of 0.5 L KH solution in a dose-dependent manner (P<0.01). In addition, 1.5 g Na₂SO₃ reduced the PO₂ of 0.5 L KH solution to 20~40 mmHg and maintained the hypoxic state for at least 90 min (suitable for HPV model in vitro), but had nearly no effect on the PCO₂, pH and Na⁺ levels. CONCLUSION: The hypoxia solution for HPV model could be reached by Na₂SO₃ in open air and the method is simple, easily feasible and stable.     

Effects of different HA/ZrO2 composites on adherence,proliferation and osteogenesis of cultured MSCs

AIM: To study the adherence, proliferation and osteogenesis effects of different composites on cultured mesenchymal stem cells (MSCs). METHODS: Zirconium oxide (ZrO₂) with monolayer hydroxyapatite (HA) composite and ZrO₂ with gradient HA composite were prepared using dry-laying method. The surface topography of the composites was observed. The rabbit MSCs were isolated and cultured on HA/ZrO₂ monolayer composite, HA/ZrO₂ gradient composite, pure HA or pure ZrO₂ slices. The adherence, proliferation and osteogenesis of the MSCs were assayed. The activity of alkaline phosphatase was detected. The mRNA expression of collagen I, osteocalcin and osteopontin was determined by RT-PCR. RESULTS: The discontinuous or continuous HA surface was observed in HA/ZrO₂ monolayer composite,while the surface of prepared HA/ZrO₂ gradient composite was fairly rough with porosity. The X-ray diffraction analysis shows that after megatemperature sintering, the ZrO₂ phase on the surface of the composite still remained, while the HA phase transformed to β-Ca₃(PO₄)₂(β-TCP), α-Ca₃(PO₄)₂(α-TCP) and CaZrO₃ phases. Cell culture showed that the HA/ZrO₂ gradient composite was in favour of cell adherence. The alkaline phosphatase activity in MSCs on pure HA slice was significantly increased compared compared with other groups.The mRNA expression of collagen I, osteocalcin and osteopontin in MSCs on HA/ZrO₂ composites and pure HA silice was higher than that in control group,especially the expression of collagen I. CONCLUSION: The HA/ZrO₂ garded composite promotes the proliferation of MSCs to a certain extent, and also promotes the osteogenesis differentiation of MSCs.     

Preliminary study of genotoxicity of HA/ZrO2 composite particles in vitro

AIM: To evaluate the genotoxicity of the hydroxyapatite/ZrO₂(HA/ZrO₂) composite particles by using the in vitro micronucleus test (MNT). METHODS: The HA/ZrO₂ composite particles prepared by sintering at high temperature and pressure using the powder of HA and ZrO₂ with different proportions were compared with the pure HA particle and pure ZrO₂ particle. The suspension of the composite particles was made. The rabbit mesenchymal stem cells were isolated and cultured. The promotive effect of the composite particles on the proliferation of the rabbit mesenchymal stem cells was detected by MTT method. The genotoxicity of the composite particles to the rabbit mesenchymal stem cells was measured by MNT method. RESULTS: The MTT test showed that both of the pure HA particle and the composite particles containing HA promoted the proliferation of rabbit mesenchymal stem cells. However, no promotive effect of the pure ZrO₂ particle on the proliferation of rabbit mesenchymal stem cells was observed. The MNT test showed no significant difference between HA group and negative control group (P>0.05), and significant difference between HA group and positive control group (P<0.05). The difference between ZrO₂ group and negative control group was significant (P<0.01), and the difference between ZrO₂ group and positive control group was insignificant (P>0.05). CONCLUSION: The increase in genotoxicity of HA/ZrO₂ composite particle is dependent on the proportion of ZrO₂ and the concentration of the composite. The 30%wt HA/70%wt ZrO₂ composite at the concentration of 200 mg/L shows significant genotoxicity.     

Cellular biological effects of matrine on K562 and K562/Vin cells

AIM: To investigate the cellular biological effects of matrine on K562 and K562/Vin cells and discuss the anticancer mechanism of matrine. METHODS: MTT assay was used to detect the IC₅₀ of matrine on these two cell lines and the reversal effect of matrine on K562/Vin cell's resistance to vincristine. In addition, the growth curve of cells was drawed. The p-glycoprotein (P-gp) expression was determined by immunohistochemistry analysis. The morphological changes of cells under light microscopy and the structural changes under transmission electron microscope were observed. RT-PCR assay was used to detect the hTERT-mRNA expression. RESULTS: The IC₅₀ of matrine was 3.4, 4.6 mmol·L ^-1 for K562 and K562/Vin cells, respectively. Matrine (4.0 mmol·L ^-1) inhibited the growth of K562, K562/Vin cells, 2.0 mmol·L ^-1 matrine inhibited expression of P-gp and with 492.4 reversal index. Matrine killed K562 cells by inducing the apoptosis and the same effect on K562/Vin cells was also observed. The hTERT-mRNA expression of K562 cells were also inhibited by matrine. CONCLUSIONS: Matrine enhanced the cytotoxicity of vincristine in K562/Vin cells, induced the apoptosis of K562 and K562/Vin cells, also inhibited the hTERT-mRNA expression in K562 cells. It shows that matrine would be an effective anticancer medicine.     

Effects of Coriaria sinica Maxim’s extract on burn wound healing and scar hyperplasia in rats based on ILK signaling pathway

AIM: To explore the mechanism of Coriaria sinica Maxim’s extract (CSME) promoting burn wound healing in the early stage and inhibiting excessive scar hyperplasia in the later stage, based on the signaling pathways, such as transforming growth factor-β₁ (TGF-β₁) regulated by integrin-linked kinase (ILK) and ILK regulated by PI3K/AKT. METHODS: Female SD rats (n=180; 180~200 g) were randomly divided into 6 groups: normal control (NC) group, vaseline (VL) group, silver sulfadiazine (SS) group and low-, medium- and high-dose of CSME (CSME-L, CSME-M and CSME-H) groups, with 30 rats in each group. Except for the rats in NC group, VL, SS, and 3 doses of CSME were applied to the wound surface of the rats in the corresponding groups every day after II° burn model was made on their waist-back in the condition of chloral hydrate anesthesia. To calculate the healing rate (HR), 10 rats in each experimental group were randomly selected to remove their wound skin for observing the pathologic change, detecting the expression of related proteins by Western blot and RT-qPCR, and checking the collagen shrinkage (SK) by fibroblast culture at the 7th, 14th, and 21st days. RESULTS: The expression of ILK, fibronectin (FN), TGF-β₁, α-smooth muscle actin (α-SMA) and integrin-β₁ (ITG-β₁) at protein and mRNA levels in wound skin of CSME groups was stronger than that in VL group and SS group at the 7th day in a dose-dependent manner, but weaker than that in VL group and SS group at the 21st day (P<0.05). Meanwhile, the protein and mRNA expression of collagen type I (Col I) in CSME groups was stronger than that in VL group and SS group from the 7th day to the 14th day, but weaker than that in VL group and SS group at the 21st day in a dose-dependent manner (P<0.05). However, the protein and mRNA expression of collagen type III (Col III) in CSME groups was weaker than that in VL group and SS group from the 7th day to the 14th day, but stronger than that in VL group and SS group at the 21st day in a dose-dependent manner (P<0.05). The SK of fibroblasts in VL group and SS group was increased continuously over time and reached its peak at 96 h. SK in CSME groups was only higher than that in VL group and SS group at 24 h and 48 h in a dose-dependent manner, but lower than that in VL group and SS group at 96 h (P<0.05). CONCLUSION: CSME promotes burn wound healing in the early stages and inhibits the scar hyperplasia in the later stages. The mechanisms may be related to its multicomponents or multiple-targets to intervene in the signaling pathways such as TGF-β₁ regulated by ILK and ILK regulated by PI3K/AKT. It may also be related to the ratio of Col I and Col III expression.     

全国设施蔬菜生产可持续发展学术研讨会在沈阳召开

会议由中国园艺学会主办 ,中国农业工程学会设施园艺工程专业委员会协办 ,沈阳农业大学园艺系承办 ,于 2 0 0 0年 4月 19日至 2 2日在沈阳农业大学召开。来自我国 13个省、自治区、直辖市的与会代表共 78人 ,会议论文 4 3篇 ,由沈阳农业大学学报专刊发表。经承办单位和与会者努力 ,会议圆满成功。开幕式由中国园艺学会副理事长李树德研究员主持 ,辽宁省科技厅、农业厅、沈阳市副食品局、沈阳农业大学的领导到会祝贺并发表讲话。会议就确定的主题进行了大会发言 ,小组讨论及现场考察。代表们欣喜地看到 ,近 2 0年来我国蔬菜设施生产迅猛发展 …