Repair of glutamate-induced excitotoxic neuronal damage mediated by intracerebroventricular transplantation of neural stem cells in adult mice.

OBJECTIVE: To investigate a possibility of repairing damaged brain by intracerebroventricular transplantation of neural stem cells (NSCs) in the adult mice subjected to glutamate-induced excitotoxic injury. METHODS: Mouse NSCs were isolated from the brains of embryos at 15-day postcoitum (dpc). The expression of nestin, a special antigen for NSC, was detected by immunocytochemistry. Immunofluorescence staining was carried out to observe the survival and location of transplanted NSCs. The animals in the MSG + NSCs group received intracerebroventricular transplantation of NSCs (approximately 1.0 x 10(5) cells) separately on day 1 and day 10 after 10-d MSG exposure (4.0 g/kg per day). The mice in control and MSG groups received intracerebroventricular injection of Dulbecco's minimum essential medium (DMEM) instead of NSCs. On day 11 after the last NSC transplantation, the test of Y-maze discrimination learning was performed, and then the histopathology of the animal brains was studied to analyze the MSG-induced functional and morphological changes of brain and the effects of intracerebroventricular transplantation of NSCs on the brain repair. RESULTS: The isolated cells were Nestin-positive. The grafted NSCs in the host brain were region-specifically survived at 10-d post-transplantation. Intracerebroventricular transplantation of NSCs obviously facilitated the brain recovery from glutamate-induced behavioral disturbances and histopathological impairs in adult mice. CONCLUSION: Intracerebroventricular transplantation of NSCs may be feasible in repairing diseased or damaged brain tissue.

[Tubeimoside I-induced ultrastructural changes of human cervical carcinoma HeLa cell line and the protective effect of cyclosporine A].

OBJECTIVE: To observe the ultrastructural changes of HeLa cells in response to tubeimoside I (TBMS1) treatment and the protective effect of cyclosporine A (CsA), and explore the role of intrinsic apoptosis pathway in TBMS1-induced HeLa cell apoptosis. METHODS: HeLa cells were treated with TBMS1 (10-50 micromo/L) alone or in combination with 2 micromol/L CsA for 12 and 24 h and observed with transmission electron microscope (TEM) for the ultrastructural changes of the cells. RESULTS: TBMS1 induced apoptosis of HeLa cells in a concentration- and time-dependant manner. Under TEM, the treated cells progressively shrunk and the intercellular space widened with loss of microvillus, mitochondrial swelling, rough endoplasmic reticulum enlargement, chromatin condensation, nuclear shrinkage and nuclear pyknosis as TBMS1 concentration increased. At low concentrations, CsA offered partial protection of the mitochondria from TBMS1-induced damage whereas high-concentration CsA did not. CONCLUSION: TBMS1 induces ultrastructural changes typical for apoptosis of the HeLa cells, which provides morphological evidence for the role of intrinsic apoptosis pathway in TBMS1-induced apoptosis.

[Saikosaponins inhibit increased glutamate and GABA expressions in the hippocampus of pentetrazole-induced slow kindling rats].

OBJECTIVE: To study the effect of saikosaponins, the active ingredients of Bupleurum chinense DC. on glutamate and GABA expressions in the hippocampus of slow kindling rats induced by pentetrazole. METHODS: Forty-eight healthy Sprague-Dawley rats were randomly divided into 6 equal groups, namely the blank control group (group A), normal saline (NS) group (group B), sodium valproate group (group C), and 3 saikosaponins groups of high, medium and small doses (groups D, E, and F, respectively). The rats in each group other than group A were given corresponding treatments after slow kindling by pentetrazole. After 4 weeks of treatment, the rats were sacrifices and the brain tissues were sampled, sliced and stained by immunohistochemically, and the results were analyzed according to the positive cell number and gray scale. RESULTS: In CA1 region, the glutamate-positive cell number and gray scale of group B was significantly different from the other groups (P<0.05), but such difference was not observed in the CA2 and DG (P>0.05); In CA1, CA2 and DG of the hippocampus, the GABA-positive cell number of group B was significantly greater but the gray scale lower than those of the other groups (P<0.05). In CA1 and CA2 regions of the hippocampus, the glutamate- and GABA-positive cell ratio of group B was significantly lower than that of the other groups (P<0.05), but in CA1, CA2, and DG region of the hippocampus, the ratio of gray scale between glutamate- and GABA-positive cells was comparable between the groups (P>0.05). CONCLUSION: The expression of glutamate and GABA, especially the latter, increased in chronic kindling rat hippocampus. Saikosaponins intervene in such changes of glutamate and GABA to contain their expressions within normal range, which may be one of the mechanisms of saikosaponins to inhibit slow kindling induced by pentetrazole.

[Effect of saikosaponins on glial fibrillary acidic protein expression in hippocampal astrocytes of pentetrazole-induced chronic kindling rats].

OBJECTIVE: To study the effect of saikosaponins, the active ingredients of Bupleurum chinense DC, on glial fibrillary acidic protein (GFAP) expression in hippocampal astrocytes of chronic kindling rats induced by pentetrazole (PTZ). METHODS: Forty-eight healthy Sprague-Dawley rats were randomized into 6 equal groups, namely the blank control group (Group A), normal saline group (Group B), sodium valproate group (Group C), and 3 saikosaponins groups of high, medium and small doses (Groups D, E, and F, respectively). The rats (except those in Group A) received intraperitoneal injection of PTZ to induce chronic kindling 1 h after the respective agents as indicated were administered intragastrically on a daily basis for 4 consecutive weeks. Upon completion of the treatment course, the rats were sacrificed and the brain tissues were sampled, sliced and stained for immunohistochemical examination. The results were analyzed to calculate the positive cell count, cross-sectional area of the cells and the gray scale. RESULTS: In group B, the positive cell population and cross-sectional area of the positive cells were the greatest among the groups (P<0.01), but the positive cell gray scale of the CA1 and CA2 regions and the dentate gyrus (DG) of the hippocampus was the lowest. The CA1 region of Group B was significantly different from that of groups A, C and D (P<0.01), and the CA2 region different from groups A, C, D and E (P<0.05), while the DG different from group F (P<0.05) and groups A, C, D and E (P<0.01). CONCLUSION: In chronic kindling rats induced by PTZ, GFAP overexpression can be inhibited by saikosaponins, which suppress the abnormal activation of hippocampal astrocyte of the kindling rats.

[Effect of saikosaponins on epileptic seizure and EEG in pentetrazole-induced chronic kindling rats].

OBJECTIVE: To study the effect of saikosaponins, the active ingredients of Bupleurum chinense DC, on epileptic seizure and EEG of pentetrazole (PTZ)-induced chronic kindling rats. METHODS: Forty-eight healthy Sprague-Dawley rats were randomly divided into 6 equal groups, namely the blank control group, normal saline (NS) group, sodium valproate (VPA) group, and 3 saikosaponins groups of high, medium and small doses. Except those in the blank control group, the rats in the other groups were all given different treatments as specified prior to intraperitoneal PTZ injection to induce kindling on a daily basis for 4 consecutive weeks. Epileptic seizures of the rats were recorded during the treatment and EEG recorded at the end of the treatments. RESULTS: Seizure frequency in the 3 saikosaponins groups decreased 2 weeks later, which was especially obvious in the high-dose group (P<0.05). The kindling rate was significantly lower in high-dose saikosaponins group than in the other treatment groups after 4 weeks of the treatment (P<0.05), with also less intense seizure onset (P<0.01) and differences in the wave form of EEG. CONCLUSION: Saikosaponins can inhibit PTZ-induced epileptic seizure in kindling rats and antagonize the kindling effect of PTZ.

[Role of mitochondria in Tubeimoside I-mediated apoptosis in human cervical carcinoma HeLa cell line].

OBJECTIVE: To investigate the role of mitochondria in TBMS1-medited apoptosis of human cervical carcinoma HeLa cell line. METHOD: Mitochondrial transmembrane potentia (deltapsim) was assayed by flow cytometry. Apoptotic induction by TBMS1 was determined by gel electrophoresis of fragmented DNA. Cytochrome c (Cyt c) was detected by Western blotting. RESULT: The results showed that TBMS1 induced apoptosis in HeLa cells, that TBMS1 decreased deltapsim and facilitated Cyt c release, and that TBMS1 induced apoptosis of HeLa cells dose-and time-dependently in accordance with increase of cytosolic Cyt c. TBMS1 had direct effect on isolated rat mitochondria which induced a time- and dose-dependent release of Cyt c from mitochondria. The results also showed that CsA protected partly HeLa cells from the effect of TBMS1. CONCLUSION: The mitochondrial apoptosis pathway has effects on TBMS1 induced human cervical carcinoma HeLa cell line apoptosis.

[Apoptosis of human nasopharyngeal carcinoma CNE-2Z cells induced by tubeimoside I].

BACKGROUND & OBJECTIVE: Tubeimu, Bolbostemma pani- culatum(Maxim.) Franquet (Cucurbitaceae), is a kind of traditional Chinese medicinal herb. Our previous studies revealed that tubeimoside I, a triterpenoid saponin isolated from the tubers of Bolbostemma paniculatum, showed potent antitumor effect. This study was designed to investigate the effect of tubeimoside I on the apoptosis of human nasopharyngeal carcinoma cell line CNE-2Z. METHODS: Cell growth inhibition mediated by tubeimoside I was measured by MTT assay after treatment with tubeimoside I. The effect of tubeimoside I on apoptotic induction in CNE-2Z cells was determined using the fluorescent microscopy, electronic microscopy,DNA agarose gel electrophoresis, and flow cytometry,respectively. Western blot analysis was performed to detect the changes of apoptosis-related genes bcl-2 and bax protein expression. RESULTS: Tubeimoside I displayed growth inhibitory activity against CNE-2Z cells with IC(50) values of 32.5, 20.7, and 16.7 micromol/L for 24, 48, and 72 hours, and CNE-2Z cells showed typical apoptotic morphological features observed by fluorescent microscopy and electronic microscopy. In CNE-2Z cells occurred typical "Ladder"bands after being exposed to tubeimoside I (10 micromol/L, 24, 48, 72 hours; 30, 40, 50, 60 micromol/L, 12 hours). Sub-G1 peak was found using flow cytometry. When CNE-2Z cells were exposed to tubeimoside I (50 micromol/L, 12 hours), the apoptosis index was 72.8%. The down regulation and phosphorylation of bcl-2 (an inhibitor of apoptosis) were detected at 1 hour after the addition of tubeimoside I. In contrast, the levels of bax appeared to be significantly upregulated at 1, 3, 5, and 24 hours after the addition of tubeimoside I. CONCLUSION: Tubeimoside I can induce the apoptosis of CNE-2Z cells, and the induction of apoptosis by tubeimoside I is closely associated with downregulation and phosphorylation of bcl-2 and bax activation.

[Cell cycle arrest and apoptosis induced by tubeimoside in HeLa cell].

BACKGROUND & OBJECTIVE: Tubeimoside, which is composed of tubeimoside I (79%) and II (21%), was isolated from the tubers of Bolbostemma paniculatum (Maxim) Franquet (Cucurbitaceae), a traditional Chinese medicine, "Tu-Bei-Mu". This study was designed to investigate the anti-tumor mechanism of tubeimoside. METHODS: Growth inhibition was measured by MTT assay. Induction of cell cycle arrest and apoptosis was determined by flow cytometry, fluorescence and electron microscopy, and gel electrophoresis of fragmented DNA. RESULTS: Tubeimoside display strong growth inhibitory effect in a dose- and time-dependant manner against HeLa cells with estimated IC50 values of 20.0, 18.8, and 8.8 mumol/L after 24, 48, and 72 h of treatment with tubeimoside. The flow cytometry profiles revealed that treatment with tubeimoside (5 h; 15, 30, 35 mumol/L) led to a dose-dependant shift from 9.80% up to 21.90%, and 27.00% in percentage of cells with a G2/M-like DNA content. On the other hand, treatment with tubeimoside (12 h, 15, 30, 35 mumol/L) led to a time-dependant shift from 8.20% up to 21.40%, 31.15%, and 34.55%, respectively. Exposure of HeLa cells to 40 mumol/L of tubeimoside induced nuclear shrinkage, chromation condensation and margination against nuclear envelope, subdiploid peak, and DNA fragmentation, characteristic as seen in apoptotic cells. CONCLUSION: Induction of cell cycle arrest and apoptosis may play an important role in the anti-tumor effect of tubeimoside.