Huali Xu

Anti-proliferative effect of Juglone from Juglans mandshurica Maxim on human leukemia cell HL-60 by inducing apoptosis through the mitochondria-dependent pathway.

Induction of apoptosis in tumor cells has become the major focus of anti-tumor therapeutics development. Juglone, a major chemical constituent of Juglans mandshurica Maxim, possesses several bioactivities including anti-tumor. Here, for the first time, we studied the molecular mechanism of Juglone-induced apoptosis in human leukemia HL-60 cells. In the present study, HL-60 cells were incubated with Juglone at various concentrations. Occurrence of apoptosis was detected by Hoechst 33342 staining and flow cytometry. Expression of Bcl-2 and Bax mRNA was determined by quantitative polymerase chain reaction (qPCR). The results showed that Juglone inhibits the growth of human leukemia HL-60 cells in dose- and time-dependent manner. Topical morphological changes of apoptotic body formation after Juglone treatment were observed by Hoechst 33342 staining. The percentages of Annexin V-FITC-positive/PI negative cells were 7.81%, 35.46%, 49.11% and 66.02% with the concentrations of Juglone (0, 0.5, 1.0 and 1.5 microg/ml). Juglone could induce the mitochondrial membrane potential (DeltaPsim) loss, which preceded release of cytochrome c (Cyt c), Smac and apoptosis inducing factor (AIF) to cell cytoplasm. A marked increased of Bax mRNA and protein appeared with Juglone treatment, while an evidently decreased of Bcl-2 mRNA and protein appeared at the same time. These events paralleled with activation of caspase-9, -3 and PARP cleavage. And the apoptosis induced by Juglone was blocked by z-LEHD-fmk, a caspase-9 inhibitor. Those results of our studies demonstrated that Juglone-induced mitochondrial dysfunction in HL-60 cells trigger events responsible for mitochondrial-dependent apoptosis pathways and the elevated ratio of Bax/Bcl-2 was also probably involved in this effect.

Effect of ginsenoside Rb3 on myocardial injury and heart function impairment induced by isoproterenol in rats

The present study was designed to evaluate the effect of ginsenoside Rb3 on myocardial injury and heart function impairment induced by isoproterenol in rats. To induce myocardial ischemia, Sprague-Dawley rats were subcutaneously injected with isoproterenol (20mg/kg). Cardiac marker enzymes and antioxidative parameters in left ventricles were measured. Hemodynamic parameters were monitored and recorded as well. Histopathological examination of left ventricles was performed. It was found that the levels of creatine kinase and lactate dehydrogenase in isoproterenol-treated rats were significantly increased. The rats administrated with isoproterenol showed the declines in left ventricular systolic pressure, positive and negative maximal values of the first derivative of left ventricular pressure, and an elevation of left ventricular end diastolic pressure. Isoproterenol enhanced the content of malondialdehyde and decreased the activities of superoxide dismutase, catalase in left ventricles. Administration of ginsenoside Rb3 significantly ameliorated myocardial injury and heart function impairment induced by isoproterenol. The cardioprotective effect of ginsenoside Rb3 was further confirmed by histopathological examination. Ginsenoside Rb3 also alleviated the increase of malondialdehyde content and decrease of superoxide dismutase and catalase activities in left ventricles. The results indicated that ginsenoside Rb3 possesses the effect against isoproterenol-induced myocardial injury and heart function impairment, and that the mechanism of pharmacological action was related to the antioxidant activity of ginsenoside Rb3 at least in part.

20(S)-Protopanaxadiol Triggers Mitochondrial-Mediated Apoptosis in Human Lung Adenocarcinoma A549 Cells via Inhibiting the PI3K/Akt Signaling Pathway

20(S)-Protopanaxadiol (PPD), an aglycone saponin ginsenoside isolated from Panax quinquefolium L, has been shown to inhibit the growth and proliferation in several cancer lines. However, the underlying molecular mechanisms remain poorly understood. In this study, we investigated the apoptosis-induced effects and the mechanism of 20(S)-PPD on human lung adenocarcinoma A549 cells. 20(S)-PPD showed a potent antiproliferative activity against A549 cells by triggering apoptosis. 20(S)-PPD-induced apoptosis was characterized by a dose-dependent loss of the mitochondrial membrane, release of cytochrome c, second mitochondria-derived activator of caspase (Smac) and apoptosis-inducing factor (AIF), activation of caspase-9/-3, and cleavage of poly (ADP-ribose) polymerase (PARP). Caspase-dependence was indicated by the ability of the pan-caspase inhibitor z-VAD-fmk to attenuate 20(S)-PPD-induced apoptosis. After treatment with 20(S)-PPD, the proportion of A549 cells at the G0/G1 phase increased, while cells at the S and G2/M phases decreased. Furthermore, 20(S)-PPD also triggered down-regulation of phosphorylated Akt (Ser473/Thr308) and glycogen synthase kinase 3β (GSK 3β). Knockdown of GSK 3β with siRNA promoted the apoptotic effects of 20(S)-PPD. These results revealed an unexpected mechanism of action for this unique ginsenoside: triggering a mitochondrial-mediated, caspase-dependent apoptosis via down-regulation of the PI3K/Akt signaling pathway in A549 cells. Our findings encourage further studies of 20(S)-PPD as a promising chemopreventive agent against lung cancer.

Ginsenoside Rb3 inhibits angiotensin II-induced vascular smooth muscle cells proliferation.

This study was designed to examine the effect of ginsenoside Rb3 on angiotensin (Ang) II-induced proliferation of cultured rat vascular smooth muscle cells (VSMCs). VSMCs proliferation was evaluated by [3H]Thymidine incorporation. The cell cycle was examined by flow cytometry. The expression of mRNA of proto-oncogene c-myc, c-fos and c-jun was observed by RT-PCR. Ginsenoside Rb3 had no effects on VSMCs proliferation in physiological condition. Ang II significantly increased the proliferation of VSMCs and the expression of mRNA of proto-oncogene c-myc, c-fos and c-jun. Ginsenoside Rb3 markedly inhibited Ang II-induced VSMCs proliferation. Concomitantly, ginsenoside Rb3 decreased cell cycle progression from G(0)/G(1) to S phase. Furthermore, ginsenoside Rb3 significantly attenuated the expression of mRNA of proto-oncogene c-myc, c-fos and c-jun. This study showed that ginsenoside Rb3 inhibited Ang II-induced VSMCs proliferation, at least in part by inhibiting Ang II-induced G(0)/G(1) to S phase transition and attenuating the expression of mRNA of c-fos, c-jun and c-myc. The findings may explain the beneficial effects of ginsenoside Rb3 in cardiovascular diseases, and it will be useful to develop prevention and therapeutics of cardiovascular diseases.

20(S)-Protopanaxadiol Induces Human Breast Cancer MCF-7 Apoptosis through a Caspase-Mediated Pathway

20(S)-Protopanaxadiol (PPD), a ginsenoside isolated from Pananx quinquefolium L., has been shown to inhibit growth and proliferation in several cancer cell lines. The aim of this study was to evaluate its anticancer activity in human breast cancer cells. MCF-7 cells were incubated with different concentrations of 20(S)-PPD and cytotoxicity was evaluated by MTT assay. Occurrence of apoptosis was detected by DAPI and Annexin V-FITC/PI double staining. Mitochondrial membrane potential was measured with Rhodamine 123. The Bcl-2 and Bax expression were determined by Western blot analysis. Caspase activity was measured by colorimetric assay. 20(S)-PPD dose-dependently inhibited cell proliferation in MCF-7 cells, with an IC50 value of 33.3 μM at 24h. MCF-7 cells treated with 20(S)-PPD presented typical apoptosis, as observed by morphological analysis in cell stained with DAPI. The percentages of annexin V-FITC positive cells were 8.92%, 17.8%, 24.5% and 30.5% in MCF-7 cells treated with 0, 15, 30 and 60μM of 20(S)-PPD, respectively. Moreover, 20(S)-PPD could induce mitochondrial membrane potential loss, up-regulate Bax expression and down-regulate Bcl-2 expression. These events paralleled activation of caspase-9, -3 and PARP cleavage. Apoptosis induced by 20(S)-PPD was blocked by z-VAD-fmk, a pan-caspase inhibitor, suggesting induction of caspase-mediated apoptotic cell death. In conclusion, the 20(S)-PPD investigated is able to inhibit cell proliferation and to induce cancer cell death by a caspase-mediated apoptosis pathway.

Acanthopanax senticosides B ameliorates oxidative damage induced by hydrogen peroxide in cultured neonatal rat cardiomyocytes.

Acanthopanax senticosides B is a monomer of Acanthopanax senticosus saponins. Previous reports showed that Acanthopanax senticosus saponins exhibit antioxidant action and cardiac protection. However, whether Acanthopanax senticosides B has cardiac protection remains unknown. In this study, we investigated the effect of Acanthopanax senticosides B on oxidative damage induced by hydrogen peroxide (H(2)O(2)) of cardiomyocytes. As revealed from the results, when the cardiomyocytes were exposed to H(2)O(2) for designed time and concentration, the percentage of survival cells was down significantly, the activity of lactate dehydrogenase (LDH) and the content of cellular malondialdehyde (MDA) were increased markedly. These results indicated that the cells were subjected to oxidative damage. Treatment with Acanthopanax senticosides B prior to H(2)O(2) (100 microM) exposure can increase cell viability significantly, lessen H(2)O(2)-induced cardiomyocyte morphological change, and inhibit augmentation of LDH activity in culture media and cellular MDA content markedly. Our results demonstrated that Acanthopanax senticosides B (400 microg/ml and 200 microg/ml) can protect cells against oxidative injury of H(2)O(2) (100 microM). Furthermore, the activities of superoxide dismutase (SOD), glutathione peroxidase, catalase and the content of reduced glutathione (GSH) of cardiomyocytes were also raised by Acanthopanax senticosides B. Taken together, the study implicated that Acanthopanax senticosides B protects cardiomyocytes against oxidative-stress injury induced by H(2)O(2) through reduction of lipid peroxidation and enhancement of the activity of antioxidant defense.

Protective effect of Panax quinquefolium 20(S)‑protopanaxadiol saponins, isolated from Pana quinquefolium, on permanent focal cerebral ischemic injury in rats

Oxidative stress is significant in the pathogenesis of cerebral ischemia. Panax quinquefolium 20(S)-protopanaxadiol saponins (PQDS) have been demonstrated to exhibit a variety of biological effects in the cardiovascular system as a result of their antioxidant properties. However, little is known regarding the effect of PQDS on cerebral ischemia. The purpose of this study was to investigate whether PQDS exhibited protective effects against cerebral ischemia. A model of cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats. Adult male rats were randomly divided into five groups: Sham, MCAO and PQDS treatment groups at doses of 12.5, 25.0 and 50.0 mg/kg. The effects of PQDS on neurological deficits, cerebral infarct area, brain water content, and the malondialdehyde (MDA) and Ca2+ levels and Na+-K+-ATPase and superoxide dismutase (SOD) activities in the brain tissue were analyzed, and the nitric oxide (NO) content and nitric oxide synthase (NOS) activity in the serum were evaluated. Moreover, the expression of Bcl-2 was analyzed using western blotting. Pretreatment with PQDS (25.0 and 50.0 mg/kg) significantly reduced the neurological deficit score, decreased the infarcted area and decreased the brain water content from 83.09 to 80.27% (P<0.05). In addition, PQDS pretreatment decreased the NOS activity and the NO levels in the serum compared with those in the MCAO group. Furthermore, pretreatment with PQDS (25.0 and 50.0 mg/kg) significantly increased the activities of SOD and Na+-K+-ATPase and decreased the levels of Ca2+ and MDA in the brain tissue (P<0.05) compared with those in the MCAO group. Pretreatment with PQDS (25.0 and 50.0 mg/kg) also increased the protein expression level of Bcl-2 compared with that in the MCAO group. The histopathological results demonstrated the protective effect of PQDS on ischemic injury. The results indicated that PQDS has protective effects against ischemic injury in rats. The mechanism may be associated with the inhibition of oxidative stress and apoptosis.

Ginsenoside Rg3 Improves Cardiac Function after Myocardial Ischemia/Reperfusion via Attenuating Apoptosis and Inflammation.

Objectives. Ginsenoside Rg3 is one of the ginsenosides which are the main constituents isolated from Panax ginseng. Previous study demonstrated that ginsenoside Rg3 had a protective effect against myocardial ischemia/reperfusion- (I/R-) induced injury. Objective. This study was designed to evaluate the effect of ginsenoside Rg3 on cardiac function impairment induced by myocardial I/R in rats. Methods. Sprague-Dawley rats were subjected to myocardial I/R. Echocardiographic and hemodynamic parameters and histopathological examination were carried out. The expressions of P53, Bcl-2, Bax, and cleaved caspase-3 and the levels of TNF-α and IL-1β in the left ventricles were measured. Results. Ginsenoside Rg3 increased a left ventricular fractional shortening and left ventricular ejection fraction. Treatment with ginsenoside Rg3 also alleviated increases of left ventricular end diastolic pressure and decreases of left ventricular systolic pressure and ±dp/dt in myocardial I/R-rats. Ginsenoside Rg3 decreased apoptosis cells through inhibiting the activation of caspase-3. Ginsenoside Rg3 also caused significant reductions of the contents of TNF-α and IL-1β in left ventricles of myocardial I/R-rats. Conclusion. The findings suggested that ginsenoside Rg3 possessed the effect of improving myocardial I/R-induced cardiac function impairment and that the mechanism of pharmacological action of ginsenoside Rg3 was related to its properties of antiapoptosis and anti-inflammation.

Metformin ameliorates diabetic nephropathy in a rat model of low-dose streptozotocin-induced diabetes

The present study aimed to explore the renoprotective effect of metformin on diabetic nephropathy in type 2 diabetic rats. A rat model of type 2 diabetic nephropathy (T2DN) was successfully induced via a high-fat diet combined with a single low-dose of streptozotocin. Metformin was administered intragastrically for 13 weeks, and fasting blood glucose (FBG), total cholesterol (TC), triglycerides (TG), HDL-c, LDL-c, urinary and serum creatinine levels were subsequently examined at the end of administration. Renal function was determined after the treatment protocol. Expression levels of transforming growth factor (TGF)-β1 and connective tissue growth factor (CTGF) were assessed via immunohistochemical analysis. Superoxide dismutase activity, malondialdehyde content and glutathione peroxidase levels were assessed in kidney tissues using commercially available kits. The results of the present study demonstrated that metformin administration significantly decreased the levels of serum blood urea nitrogen, serum creatinine, creatinine clearance, urinary albumin excretion and fasting blood glucose in rats with T2DN. Furthermore, TG, TC and LDL-c levels were significantly decreased following metformin treatment, whereas HDL-c was increased. Metformin treatment significantly increased SOD activity and significantly decreased malondialdehyde levels, as compared with the model group. It was also demonstrated that metformin administration significantly decreased the expression levels of TGF-β1 and attenuated the morphological changes associated with T2DN in rats. These data clearly demonstrated the renoprotective effects of metformin against the development and progression of T2DN in rats. The underlying mechanism of this protective effect may be associated with glycemic control, lipid metabolism, and anti-oxidative and anti-inflammatory functions.

Neuroprotective effects of Kaempferide-7-O-(4″-O-acetylrhamnosyl)-3-O-rutinoside on cerebral ischemia-reperfusion injury in rats

In the present study, we aim to evaluate the potential neuroprotective effect and the underlying mechanism of Kaempferide-7-O-(4″-O-acetylrhamnosyl)-3-O-rutinoside (A-F-B) against cerebral I/R injury. Adult male rats were pretreated with A-F-B by intragastric administration once a day for 3 days. One hour after the third day administration, animals were subjected to 2h of transient middle cerebral artery occlusion (MCAO) followed by 24h of reperfusion. Neurological deficit, infarct volume, histopathological changes, oxidative stress-related biochemical parameters, neuronal apoptosis, apoptosis-related proteins and the expression of pro-inflammator cytokines genes were measured. A-F-B significantly decreased neurological and histological deficits, reduced the infarct volume, and decreased neuroapoptosis. Meanwhile, A-F-B inhibited the expression of Bax, cleaved caspase-3, cleaved caspase-9, and promoted Bcl-2 expression. In addition, the expression of pro-inflammator cytokines, including phospho-NF-kBp65, interleukin-1β, interleukin-6, tumor necrosis factor-α, intercellular adhesion molecule-1, cyclooxygenase-2 and inducible nitric oxide synthase, were also suppressed by A-F-B pretreatment. Furthermore, pretreatment with A-F-B could significantly increase the activities of superoxide dismutase, glutathione peroxidase, but decrease the content of malondiadehyde in blood serum. These results suggest that A-F-B has the neuroprotective effect in ischemic stroke by suppressing neuroinflammation, reactive oxygen species and neuroapoptosis.