Matrine attenuates bleomycin-induced pulmonary injury partially via modulating mononuclear phagocyte phenotype switching in mice

AIM: To investigate the influence of matrine (MA) on the phenotype switching of mouse monocytes and alveolar macrophages induced by bleomycin (BLM).METHODS: All mice were randomly divided into normal saline (NS) group, BLM group, BLM+NS group and BLM+MA group. The mice were administered with BLM at 2.5 mg/kg via oropharyngeal instillation. The mice in BLM+MA group were treated with MA (15 mg·kg^-1·d^-1) by oral gavage following BLM administration. The mice were sacrificed on days 3, 7, 14, and 21. The lungs were removed for pathological analysis. The circulating monocyte subsets and polarization state of bronchoalveolar lavage fluid (BALF)-derived alveolar macrophages were analyzed by flow cytometry.RESULTS: The results of HE and Masson trichrome staining in BLM and BLM+NS groups exhibited classical pathological stages of lung fibrosis, including acute inflammation phase and later fibrosis phase. Compared with BLM+NS group, MA treatment alleviated the inflammatory response and the degree of fibrosis induced by BLM (P<0.05). There was a rapid change of circulating Ly6C^hi monocytes and its magnitude was positively associated with the pulmonary inflammatory response. An expansion of M2-like alveolar macrophages was positively correlated with the magnitude of lung fibrosis. Moreover, MA treatment partially normalized the phenotype switching of monocytes and alveolar macrophages.CONCLUSION: Matrine treatment attenuates BLM-induced pulmonary injury partially via modulating the phenotype switching of monocytes and alveolar mocrophages.     

Acetyl-L-carnitine attenuates H2O2-induced oxidative damage of PC12 cells

AIM: To investigate the effect of acetyl-L-carnitine (ALC) on H₂O₂-induced oxidative damage in PC12 cells and its possible mechanism. METHODS: A moderate oxidative damage PC12 cell model was induced by exposure of the PC12 cells to H₂O₂. ALC at different concentrations (100, 200 and 400 μmol/L) was applied to the PC12 cells cultured in vitro, and CCK8 assay was used to detect the cell viability. The cells were divided into control group, H₂O₂ group, and low-ALC, medium-ALC and high-ALC groups. The apoptosis of the cells was analyzed by flow cytometry. The protein levels of Nrf2 and cleaved caspase-3 were determined by Western blot. The nuclear translocation of Nrf2 was observed by immunofluorescence staining. RESULTS: ALC at different concentrations (100, 200 and 400 μmol/L) significantly inhibited H₂O₂-induced PC12 cell apoptosis, and the medium concentration group had the best effect. Compared with H₂O₂ group, low, medium and high concentrations of ALC significantly increased the viability of the PC12 cells induced by H₂O₂, inhibit cell apoptosis (P<0.05), significantly down-regulated the protein level of cleaved caspase-3 (P<0.05), up-regulated the protein level of Nrf2 (P<0.05), and promoted the translocation of Nrf2 from the cytoplasm to the nucleus. CONCLUSION: Acetyl-L-carnitine attenuates H₂O₂-induced oxidative damage of PC12 cells, inhibits the apoptosis and increases the viability, which is related to the activation of Nrf2 signaling pathway.     

Role of miR-486-5p in apoptosis of human bone marrow mesenchymal stem cells induced by hydrogen peroxide

AIM: To investigate the role of microRNA-486-5p (miR-486-5p) in the apoptosis of human bone marrow mesenchymal stem cells (hMSCs) induced by hydrogen peroxide (H₂O₂). METHODS: The hMSCs were cultured in vitro and exposed to serum-free medium and H₂O₂ (10 mmol/L). The changes of miR-486-5p expression in oxidative stress-related apoptosis of hMSCs were measured by real-time PCR. The hMSCs were transfected with miR-486-5p mimic or inhibitor at concentration of 30 nmol/L by Lipofectamine RNAiMAX. The effect of miR-486-5p on H₂O₂-induced decrease in cell viability was evaluated by MTT assay. Hoechst 33342 staining and flow cytometry were applied to determine the role of miR-486-5p in the apoptosis of hMSCs. The protein expression was evaluated by Western blotting. Caspase-3 activity was determined using a caspase-3 activity kit. RESULTS: Compared with control group, the expression of miR-486-5p significantly decreased after treated with H₂O₂ (P<0.05). In addition, over-expression of miR-486-5p in the hMSCs reduced the cell viability, accelerated apoptosis, down-regulated Bcl-2/Bax ratio, caspase-3 enzyme precursor content and phosphorylation of Akt, and activated caspase-3 activity. Conversely, down-regulation of miR-486-5p significantly inhibited H₂O₂-induced cell apoptosis and the caspase-3 activity, increased cell viability and up-regulated Bcl-2/Bax ratio and phosphorylation level of Akt. CONCLUSION: Over-expression of miR-486-5p promotes H₂O₂-induced hMSCs apoptosis, and repression of miR-486-5p protects hMSCs from H₂O₂-induced cellular apoptosis, which may be mediated by regulating Akt signaling pathway.     

Limb ischemic preconditioning protects human umbilical vein endothelial cells from oxidative stress induced by H2O2

AIM: To investigate the effects of the sera from the rats after limb ischemic preconditioning (LIPC) on human umbilical vein endothelial cells (HUVECs) injured by hydrogen peroxide (H₂O₂). METHODS: The HUVECs were divided into 5 groups: the cells in control group were cultured without any intervention; the cells in model group (M) were damaged by 1 mmol/L H₂O₂ for 2 h; the cells in early preconditioning serum (EPS) group, delayed preconditioning serum (DPS) group or sham limb ischemic preconditioning serum (SPS) group were treated with the corresponding serum at 5% for 12 h, respectively, and then treaed with H₂O₂ for 2 h. The viability of the HUVECs was analyzed by flow cytometry. The lactate dehydrogenase (LDH) in the culture media was detected. The cell adhesion molecules in the HUVECs were detected by real-time PCR. The mRNA and protein expression of heme oxygenase-1 (HO-1) was also determined. RESULTS: The viability of HUVECs incubated with 1 mmol/L H₂O₂ for 2 h significantly decreased compared with the control cells, which was accompanied with the augmentations of LDH in the medium and the cell adhesion molecules in cells, such as vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). Preincubation with EPS and DPS derived from the rats subjected LIPC attenuated these injuries. Furthermore, pretreatment with EPS and DPS increased the expression of HO-1 at mRNA and protein levels. CONCLUSION: LIPC protects the HUVECs from H₂O₂-induced injury.     

Protective effect of HSP70 on injuried myocardial cells induced by H2O2

AIM: To investigate the role of heat-shock protein 70(HSP₇₀) in the protection of myocardial cells against ischemic injury.METHODS: Myocardial cells were cultured in vitro. HSP₇₀ was induced by hyperthermia. H₂O₂-injured myocardial cells were divided into different groups. Flow cytometry, DNA Ladder and biochemistry methods were employed to observe the myocardial cells of different groups.RESULTS: Immunohistochemistry showed hyperthermia induced the up-regulation of HSP₇₀ in myocardial cells. Apoptotic rate, activity analysis of cytochrome C and succinic dehydrogenase in H₂O₂-injuried and HSP₇₀-protected groups were obviously different. Electron micrograph shomed hyperthermia alliviated myocardial cell injury induced by H₂O₂. CONCLUSION: HSP₇₀ delays apoptosis and protects against H₂O₂-induced myocardial cell injury.     

Effects of 6-gingerol on apoptosis of rat nucleus pulposus cells

AIM: To study the effect of 6-gingerol on the apoptosis of rat nucleus pulposus cells and its possible mechanism. METHODS: Rat nucleus pulposus cells were isolated and cultured. The effects of 6-gingerol and hydrogen peroxide (H₂O₂) at different concentrations on the viability of nucleus pulposus cells were measured by CCK-8 assay. After 6-gingerol treatment, the protein level of p-Akt was determined by Western blot. The cells were divided into 4 groups:control group, H₂O₂ group, 6-gingerol group (6-gingerol + H₂O₂) and LY294002 group (6-gingerol + H₂O₂ + LY294002). The apoptotic rate and the levels of reactive oxygen species (ROS) were analyzed by flow cytometry. TUNEL fluorescence staining was used to observe the number of apoptotic cells. The morphological changes of mitochondria were observed under transmission electron microscope, and Western blot was used to determine the protein levels of caspase-3, Bcl-2, Bax, p-Akt, Akt and p53. The mRNA expression of aggrecan and type II collagen was measured by RT-qPCR. RESULTS: The results of CCK-8 assay showed that the optimal concentration of 6-gingerol for promoting the viability of rat nucleus pulposus cells was 24 mg/L, and the exposure condition of H₂O₂ at 80 μmol/L for 6 h was appropriate for establi-shing the cell damage model. 6-Gingerol increased the protein level of p-Akt in a time-dependent manner. The apoptotic rate, ROS level and TUNEL positive cells in H₂O₂ group were significantly increased compared with control group. The mitochondrial edema was obvious in H₂O₂ group compared with control group. The protein levels of pro-apoptotic molecules caspase-3, Bax and p53 were significantly increased, while anti-apoptotic protein Bcl-2, and mRNA expression of aggrecan and type II collagen were significantly decreased compared with control group (P<0.05). 6-Gingerol exerted a protective effect against H₂O₂-induced apoptosis and promoted the expression of anti-apoptotic proteins. However, this effect was weakened after treatment with PI3K/Akt signaling pathway inhibitor LY294002. CONCLUSION: H₂O₂ induces damage and dysfunction of rat nucleus pulposus cells, and 6-gingerol may inhibit H₂O₂-induced apoptosis of nucleus pulposus cells by activation of PI3K/Akt signaling pathway.     

Docosahexaenoic acid protects human retinal pigment epithelial cells against oxidative stress-induced apoptosis

AIM: To observe the effect of docosahexaenoic acid(DHA) on H₂O₂-induced apoptosis in human retinal pigment epithelium cells and its molecular mechanism. METHODS: Human retinal pigment epithelium cell line ARPE-19 was cultured in vitro, and 12.5 mmol/L H₂O₂ was used to mimic the oxidative stress condition. The cells were treated with 30~100μmol/L DHA for 4~24 h. The expression of heme oxygenase-1(HO-1) at mRNA and protein levels was detected by real-time PCR and Western blot, respectively. The enzymic activity of HO-1 was measured by colorimetry. Production of reactive oxygen species(ROS) was determined by fluorescent probe. Activation of NF-E2-related factor 2(Nrf2) was examined by immunofluorescence method. Apoptosis of ARPE-19 cells was analyzed by flow cytometry. RESULTS: The mRNA and protein expression and the enzymic activity of HO-1 were significantly increased in the ARPE-19 cells after DHA treatment. Meanwhile, nuclear translocation of Nrf2 was also observed. Apoptosis appeared and ROS was produced upon H₂O₂ incubation. In contrast, DHA at 100μmol/L significantly abrogated H₂O₂-induced apoptosis and ROS production. Furthermore, silencing of HO-1 by specific siRNA, or treatment with ZnPP, an inhibitor of HO-1, partly counteracted the protective effect against H₂O₂-induced apoptosis and ROS production. CONCLUSION: DHA protects retinal pigment epithelial cells against oxidative stress via induction of heme oxygenase-1 expression after Nrf2 activation.     

Adiponectin attenuates H2O2-induced SH-SY5Y cell injury and tau hyperphosphorylation via activating PP2A

AIM: To study the effects of adiponectin on H₂O₂-induced cell injury and tau hyperphosphorylation in human neuroblastoma SH-SY5Y cells. METHODS: Cell viability was determined by MTT assay. H₂O₂-induced cell injury and morphological changes in the SH-SY5Y cells with or without adiponectin treatment were observed. The level of tau phosphorylation as well as the activities of protein phosphatase 2A(PP2A) and of glycogen synthase kinase-3β(GSK-3β) were examined by Western blotting. RESULTS: Adiponectin significantly attenuated H₂O₂-induced cell injury(P<0.01). Adiponectin upregulated the activity of PP2A and decreased phosphorylation levels of tau under the stimulation with H₂O₂ (P<0.01). Okadaic acid, a specific inhibitor of PP2A, blocked the protective effects of adiponectin(P<0.01). Adiponectin increased the phosphorylation level of GSK-3β at Ser9 site under H₂O₂ stimulation(P<0.01). CONCLUSION: Adiponectin protects SH-SY5Y cells against H₂O₂-induced cell injury and decreases tau hyperphosphorylation by activating PP2A and inactivating GSK-3β.     

会讯

AIM:To investigate the pulmonary expresson of macrophage migration inhibitory factor(MIF) in acute lung injury (ALI) rats induced by intravenous injection of oleic acid and its correlation with blood gas change, pulmonary weight index (PWI) and pulmonary pathological injuries.METHODS: ALI rats model were made by injecting oleic acid as the oleic acid group while rats injection with saline solution as control. After injecting oleic acid or saline for six hours, the PaO₂ and PaCO₂ of the left heart and pulmonary weight index were measured. At the same time, by using a microwave-base double immunohistochemistry labeling, the number of MIF^＋, ED₁⁺ (anti-CD68 antibody), ED₁⁺/MIF^＋cell in pulmonary tissue of different groups and their correlation with blood gas and pulmonary weight index were examined. RESULTS: The blood gas parameters of the oleic acid group were far worse than that of the control group (P＜0.01). The PWI of the oleic acid group was significantly higher than that of the control group (P＜0.01). There was marked upregulation of MIF expression on injured lung tissue. The number of cell expressed MIF^＋ , ED₁⁺ and MIF with ED₁ showed a strong positive correlation with PaO₂, PWI and histological changes. CONCLUSION: MIF may play a pivotal role in mediation of progressive lung injuries induced by intravenous oleic acid injection. In addition, the number of cells expressed MIF, especially macrophage, may reflect the severity of lung injury.     

Study on apoptotic and nonapoptotic injuries induced by hydrogen peroxide in cardiac myocytes

AIM: To study apoptotic injury induced by reactive oxygen species-hydrogen peroxide (H₂O₂) on cardiac myocytes.METHODS:Cultured rat neonatal cardiac myocytes were treated with H₂O₂ of various concentration to observe apoptotic injury of cardiomyocytes by agarose gel electrophoresis, Giemsa-stained smears of cell, and flow cytometry, meanwhile lactate dehydrogenas (LDH) and malondialdehyde(MDA) were determined to assess the effect of H₂O₂ on lipid peroxidation and permeability of the plasma membrane. RESULTS: 5 mmol/L H₂O₂ caused cultured cardiomyocytes apoptotic morphological characteristics, including nucleosomal DNA fragmentation in myocytes by agarose gel electrophoresis (DNA ladder), cell shrinkage, nuclear condensation, and chromatin margin by Giemsa-stained cell smears, and aneuploid peak(AP)-apoptotic bodies occurrence by flow cytometry.CONCLUSIONS: H₂O₂-induced apoptosis in myocytes was a time-and concentration-dependent process. Treatment with low concentration of H₂O₂(＜1 mmol/L) only caused cardiomyocyted early biochemical changes, such as increase of free radicals level and membrane permeability ,which were pro-apoptotic injurious features. High concentration of H₂O₂ (＞10 mmol/L) rapidly induced a necrotic form of death characterized by smeared patterns of DNA digestion on agarose gel electrophoresis and lethal membrane disruption (as measured by LDH release). Exposure of 5~10 mmol/L H₂O₂ induced cardiomyocytes apoptosis concurrently with biochemical changes of LDH and MDA increase in the medium.     

Total flavonoids of onion attenuate hydrogen peroxide-induced oxidative damage in retinal pigment epithelial cells

AIM: To investigate the effects of total flavonoids of onion (FO) on hydrogen peroxide (H₂O₂)-induced oxidative damage in retinal pigment epithelial cells. METHODS: The retinal pigment epithelium ARPE-19 cells were divided into 5 groups:control group, H₂O₂ group (treated with H₂O₂), FO-L+H₂O₂ group (treated with H₂O₂ and low concentration of FO), FO-M+H₂O₂ group (treated with H₂O₂ and medium concentration of FO) and FO-H+H₂O₂ group (treated with H₂O₂ and high concentration of FO). The cell viability was measured by MTT assay. Apoptosis was analyzed by flow cytometry. DCFH-DA staining was used to detect reactive oxygen species (ROS) level in the cells. WST assay was used to detect superoxide dismutase (SOD) activity. The content of malonaldehyde (MDA) was measured by TBA method. Mitochondrial membrane potential was analyzed by JC-1 staining. The protein levels of cytochrome C (Cyt C) in the cytoplasm, and cleaved caspase-3 and cleaved caspase-9 in the cells were determined by Western blot. RESULTS: Treatment with H₂O₂ decreased ARPE-19 cell viability, increased the apoptotic rate and the level of ROS in the cells, decreased SOD activity, increased the content of MDA, decreased mitochondrial membrane potential, and increased the protein levels of Cyt C in the cytoplasm and cleaved caspase-3 and cleaved caspase-9 in the cells (P<0.05). Compared with H₂O₂ group, the cell viability in FO-L+H₂O₂ group, FO-M+H₂O₂ group and FO-H+H₂O₂ group was increased, the apoptotic rates were decreased, the levels of ROS were decreased, SOD activity was increased, the content of MDA was decreased, mitochondrial membrane potential was increased, the protein level of Cyt C was decreased in the cytoplasm, and the protein levels of cleaved caspase-3 and cleaved caspase-9 protein in the cells were decreased gradually (P<0.05). CONCLUSION: Total flavonoids of onion reduce H₂O₂-induced oxidative damage in retinal pigment epithelial cells.     

Immunoregulatory effect of Buyang-Huanwu decoction on monocyte-macrophages in mice with experimental autoimmune encephalomyelitis

AIM: To explore the therapeutic effect of Buyang-Huanwu decoction (BYHWD) on experimental autoimmune encephalomyelitis (EAE) and its immunoregulatory effect on monocyte-macrophages.METHODS: Chronic EAE was induced by myelin oligodendrocyte glycoprotein peptide fragment 35-55 (MOG_35-55) in the female C57BL/6 mice, which were randomly divided into saline group and BYHWD group. On day 3 after immunization, the mice in BYHWD group were orally administrated with BYHWD, while normal saline was given to the control mice. The clinical score and body mass were recorded every other day. At day 17 after immunization, the mice were sacrificed and spinal cords were obtained for HE staining and myelin staining. The M1 and M2 macrophage phenotypes of splenic cells were detected by flow cytometry and immunofluorescence staining. The protein expression of iNOS, TNF-α, arginase and IL-10 in the spinal cord macrophages was determined by Western blotting.RESULTS: BYHWD delayed the onset of EAE, reduced the clinical scores of EAE, inhibited the inflammatory cell infiltration and demyelination in the spinal cord, and promoted the conversion of M1 macrophages into M2 phenotype in the spinal cord and spleen.CONCLUSION: BYHWD intervention attenuates the behavioral and pathological changes in the EAE mice, and its mechanism may be related to the macrophage conversion.     

类番茄茄与番茄属间有性杂交的研究

用类番茄茄与番茄属的 9个种进行有性杂交 ,通过人工离体胚培养获得栽培番茄‘粤农二号’×类番茄茄的F1植株。杂种近于不育。用栽培番茄、类番茄茄、野生番茄及(栽培番茄×野生番茄 )与之回交及杂交 ,获得与栽培番茄的回交子一代及与秘鲁番茄、多腺番茄、潘那利番茄、粤农二号×秘鲁番茄F1的杂种 ,但它们的能育性很低。用栽培番茄、野生番茄与它们再回交及杂交 ,未能得到与栽培番茄的二次回交子一代 ,只获得 (粤农二号×类番茄茄 )× (粤农二号×秘鲁番茄 )的F1与秘鲁番茄、多腺番茄的复合杂种。人工苗期接种黄瓜花叶病毒 (CMV)结果表明 ,类番茄茄及其与番茄属的远缘杂种对CMV有较强的抗性。     

p38 MAPK-iNOS-NO pathway mediates chemical hypoxia-induced injury in PC12 cells

AIM: To investigate the possibility that p38 MAPK-iNOS-NO pathway mediates the chemical hypoxia-induced injury in PC12 cells. METHODS: PC12 cells were treated with cobalt chloride (CoCl₂, 600 μmol/L) to set up a chemical hypoxia-induced cellular injury model. Cell viability was tested by cell counter kit-8(CCK-8). The morphological changes of the apoptotic cells were detected by Hochest33258 staining. The expression of iNOS was determined by Western blotting. Nitrite accumulation, an indicator of NO production, was measured in cell culture supernatants by Griess reagent assay. RESULTS: Exposure of PC12 cells to CoCl₂ for 24 h significantly enhanced iNOS expression. Exposure of PC12 cells to CoCl₂ for 24 h and 48 h significantly enhanced nitrite accumulation. Pretreatment with L-canavanine (an inhibitor of iNOS,5-20 μmol/L) for 60 min prior to exposure of PC12 cells to CoCl₂ protected PC12 cells against the injuries induced by CoCl₂ with enhanced cell viability and decreased amount of apoptotic cells. Pretreatment with SB203580 (an inhibitor of p38 MAPK) for 60 min prior to exposure of PC12 cells to CoCl₂ down-regulated the expression of iNOS induced by CoCl₂. CONCLUSION: p38 MAPK-iNOS-NO pathway mediates CoCl₂-induced injuries in PC12 cells.     

Protective effect of senegenin on retinal ganglion cells in oxidative stress induced injury

AIM: To evaluate the effect of senegenin (Sen) on H₂O₂-treated retinal ganglion cells (RGCs) and to explore its underlying mechanisms. METHODS: RGCs were retrograde labeled by injection of fluorogold into the superior colliculi of SD rats on the postnatal day 3. On the postnatal days 6 to 8, the retinas were dissociated with papain and cultured. Primary RGCs cultured in vitro were treated with H₂O₂ and/or various doses of Sen. The viability of RGCs was evaluated by counting the fluorescence-labeled neurons under microscope. The morphological changes of the nuclei in the retinal neurons were observed by Hoechst 33258 staining. Western blotting was applied to determine the expression of cleaved caspase-3, cytochrome C and Bcl-2 in cultured retinal neurons. RESULTS: Compared with the control cells, Sen at doses of 10, 20 or 40 μmol/L had no toxicity to RGCs (P>0.05). However, Sen at doses of 80 and 160 μmol/L had significant toxicity to RGCs (P<0.01). Compared with H₂O₂-injured group, Sen at doses of 10, 20 and 40 μmol/L effectively protected against H₂O₂-induced injury in RGCs (P<0.05) with the best efficiency at 40 μmol/L. Hoechst 33258 staining showed that the neuronal apoptosis caused by H₂O₂ was reduced by Sen. The results of Western blotting showed an up-regulation of Bcl-2, and decreased cytochrome C and cleaved caspase-3 levels by Sen in H₂O₂-treated retinal neurons. CONCLUSION: Sen is able to protect RGCs from H₂O₂-induced injury by enhancing Bcl-2 expression and inhibiting cell apoptosis.     

The effect of L-arginine on protein kinase C of isolated pulmonary arterial rings from rats with hypoxia-induced pulmonary hypertension

AIM: To elucidate whether the mechanism that L-arginine can relieve hypoxia pulmonary hypertension involves inhibition of the activity of protein kinase C(PKC).METHODS: Twenty-one male Wistar rats were randomly divided into NS control, hypoxia and L-arginine(500 mg·kg^-1·d^-1, ip) treatment groups. After two-weeks treatment, mean pulmonary artery pressure (mPAP), mean systematic artery pressure (mSAP) and the ratio of the weight of right ventricle to that of left ventricle plus septum were measured, then two pulmonary arterial rings were isolated to be exposed to PDBu(a specific activator of PKC ) and observed: (1) The maximal response (P₁) to 500 nmol/L PDBu, the time required to achieve a half-maximal response to 500 nmol/L PDBu (t_1/2), the time during which the maximal response to 500 nmol/L PDBu maintained (T) and the isometric responses at different times (2, 4, 8, 12, 20, 40, 60, 80 min). The isometric response was represented as the percentage of the maximal response (P₀) of the same arterial ring to 5μmol/L phenylephrine hydrochloride (P₀%). (2) Dose-response curve in response to PDBu (10-11 000 nmol/L) and the dose producing a half-maximal response in the curve (EC₅₀). RESULTS: mPAP, RV/(LV+S), P₁, T and the isometric responses at 2, 4, 8, 20 min of NS control and L-arginine treatment groups were lower than those of hypoxic group respectively (P＜0.05), while t_1/2 and EC₅₀ were all greater than those of hypoxic group respectively (P＜0.05).CONCLUSION: The activity of PKC was augmented when rats were exposed to two-weeks normobaric hypoxia, which resulted in the increased reactivity of the isolated pulmonary arterial rings. L-arginine can inhibit the activation of PKC, which is likely part of the mechanism by which L-arginine can reduce mPAP and relieve the hypertrophy of right ventricle.     

Chrysophanol ameliorates spatial memory ability of rats by inhibiting Aβ1-42-induced oxidative stress

AIM: To investigate whether chrysophanol alleviates amyloid β-protein (Aβ)-induced cognitive dysfunction and the underlying antioxidative mechanism.METHODS:Adult male Wistar rats (230~250 g) were randomly divided into control group, Aβ_1-42 group, chrysophanol group, and Aβ_1-42+chrysophanol (1, 10 and 100 mg/kg) groups. Aβ_1-42 was delivered by intracerebroventricular injection under the guidence of a brain stereotaxic apparatus. Y-maze test, open-field test and Morris water maze test were performed 1 week after Aβ_1-42 injection to evaluate the ability of rat spacial learning and memory. Chrysophanol was intraperitoneally injected once daily for 5 consecutive days. After the behavioral tests, the animals were sacrificed immediately by decapitation, and the hippocampus were collected. The malondialdehyde (MDA) content and the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) in the hippocampus were measured.RESULTS:Multiple (7 consecutive days, once daily) but not single (once a day) chrysophanol treatment at 1, 10 and 100 mg/kg effectively prevented Aβ_1-42-induced cognitive function deficits in a dose-dependent manner as shown by Y-maze test and Morris water maze test. Moreover, the Aβ_1-42-induced increase in MDA content and decrease in the activity of antioxidant enzymes (SOD, GSH-Px and CAT) in the hippocampus of the rats were also attenuated by multiple chrysophanol treatment.CONCLUSION:Repeated chrysophanol treatment attenuates Aβ_1-42-induced cognitive deficits and synaptic plasticity dysfunction, and the mechanisms underlying the neuroprotective effects are likely due to its antioxidant activity.     

CDK4-pRB-E2F1 pathway may mediate Aβ1-40-induced apoptosis in rat cortical neurons

AIM:To study the possible molecular mechanism of beta-amyloid peptide_1-40-induced apoptosis in rat cortical neurons.METHODS:40 mg/L beta-amyloid peptide_1-40 (Aβ_1-40) was used to induce apoptosis in cultured rat cortical neurons. The level of CDK4, phosphorylated pRB were detected by flow cytometry and immunoblotting; RT-PCR was used to examine the mRNA expression of E2F1 while fluorescent spectrofluorometer was used to measure caspase-3 activity. All of the above study was designed to observe whether the level of CDK4, phosphorylated pRB and E2F1 mRNA expression could be affected by Aβ_1-40.RESULTS:(1)The level of CDK4, phosphorylated pRB increased markedly 2-4 hours after treatment with Aβ_1-40, and caspase-3 activity elevated remarkably 12-24 hours after treatment with Aβ_1-40; (2) E2F1 mRNA expression was upregulated 3 hours after incubation with Aβ_1-40.CONCLUSION:Aβ_1-40 may induce apoptosis in rat cortical neurons in a manner dependent on CDK4-pRB-E2F1 pathway.     

Effects of edible-medicinal fungus crude extracts on vascular endothelial cells with high glucose-induced injury

AIM: To investigate the effects of crude extracts of Cordyceps gunnii (CGE), Lepista lentinus (LLE), Cordyceps sinensis (CSE) and Lentinus striguellus (LSE) on the proliferation of high glucose-treated human umbilical vein endothelial cells (HUVECs). METHODS: The cultured HUVECs were divided into normal control group (treated with M199 culture medium alone), high glucose group (treated with M199 culture medium containing 33 mmol/L glucose) and 4 crude extracts of edible-medicinal fungi (CGE, LLE, CSE and LSE) intervention groups (treated with the crude extract of edible-medicinal fungus at concentrations of 12.5, 25, 50, 100 mg/L in high glucose M199 culture medium). The cell proliferation was evaluated by MTT assay. The cell cycle and ROS level were measured by flow cytometry. RESULTS: Compared with normal control group, the MTT absorbance value and the percentage of G₀/G₁ stage of the HUVECs in high glucose group were significantly decreased (P<0.05), while the percentage of S+G₂/M and ROS level were significantly increased (P<0.05). Compared with high glucose group, treatment with the crude extracts of Lepista lentinus and Lentinus striguellus decreased the cell absorbance value (P<0.05), and the inhibitory effect was enhanced in a dose-dependent manner. However, Cordyceps gunnii had no effect (P>0.05). The crude extracts of Cordyceps sinensis (12.5~50 mg/L) significantly enhanced the proliferative activity of HUVECs, decreased the percentage of G₀/G₁ stage of HUVECs, increased the percentage of S+G₂/M of HUVECs, and reduced the intercellular ROS level (P<0.05). CONCLUSION: Only Cordyceps sinensis crude extract effectively protects the HUVECs in high glucose-induced injury, which might be due to promoting more cells to enter to the cell cycle and down-regulating oxidative stress.     

MSC-conditioned medium activates Nrf2/ARE pathway to protect H9c2 cells against oxidative stress

AIM: To investigate the protective effect of mesenchymal stem cell (MSC)-conditioned medium (MSCCM) on myocardial cell line H9c2 and its mechanism. METHODS: Verification of MSC was performed by flow cytometry analysis, followed by MTT assay to determine the optimal incubation time of MSCCM with myocardial cells. The cells were divided into 4 groups: normal (N) group, model (M) group, M+MSCCM group and MSCCM group. The cells in M+MSCCM group and MSCCM group were pre-incubated with MSCCM for 24 h. The cells in M group and M+MSCCM group were treated with 300 μmol/L H₂O₂ for 4 h to imitate oxidative injury of myocardial cells. Mitochondrial membrane potential and apoptotic rate of injured myocardial cells were detected by flow cytometry. The ROS production was measured by fluorescence microscopy. The nuclear translocation of Nrf2 and expression of HO-1 was examined by Western blot. RESULTS: No difference of mitochondrial membrane potential, apoptotic rate or ROS production between MSCCM group and N group was observed (P>0.05). The mitochondrial membrane potential depolarization, apoptotic rate and ROS production in M+MSCCM group were significantly lower than those in M group (P<0.01). The nuclear translocation of Nrf2 and expression of HO-1 in the myocardial cells were increased with MSCCM incubation time prolonged. CONCLUSION: MSCCM protects the myocardial cells against oxidative injury induced by H₂O₂. The anti-oxidative mechanism would be associated with the activation of Nrf2/ARE pathway.