OBJECTIVETo investigate the roles of telomere and telomerase in the effect of ginsenoside Rg1 to delay hematopoietic stem cell senescence.

METHODSca-1(+) HSC was isolated by magnetic cell sorting(MACS) and divided into five groups: the control group, the aged model group, the Rg1 group, the Rg1 treated aged group and the Rg1 delayed aged group. The changes of cells were observed by senescence-associated beta-Galactosidase (SA-beta-Gal) staining. Cell cycle assay and culture of mixed hematopoietic progenitor cell were used to investigate the effect of ginsenoside Rg1 to delay Sca-1(+) HSC senescence. Telomere length and telomerase activity were detected by southern blotting and TRAP-PCR-SYBR Green staining.

RESULTCompared with aged model group, the percentage of positive cells expressed SA-beta-Gal and the number of cells entered G1 phase were decreased and the number of colony of mixed hematopoietic progenitor was increased. It showed markedly decreased in the shortening of telomere length and reinforcing in the telomerase activity to Rg1 treated aged group and Rg1 delayed aged group. The change of Rg1 delayed aged group was significantly higher than Rg1 treated aged group.

CONCLUSIONActivation of telomerase and prolonging of telomere length might be involved in the process of ginsenoside Rg1 to delay and treat the senescence of Sca-1(+) HSC.

Cellular Senescence ; drug effects ; Ginsenosides ; pharmacology ; Hematopoietic Stem Cells ; drug effects ; physiology ; Telomerase ; metabolism ; Telomere ; drug effects

This study was purposed to investigate the effect of chemotherapeutic drug cyclophosphamide (CTX) on normal murine bone marrow hematopoietic cells, especially on the self-renewal, proliferation and differentiation of bone marrow hematopoietic cells, and possible mechanisms. The CTX-treated mouse model was established by CTX 200 mg/kg, ip. The exact time of complete recovery of hematopoiesis was determined by monitoring the recovery level of differential blood counts and the proportion of LKS(+) cells in bone marrow cells. The function of bone marrow hematopoietic cells such as self-renewal, proliferation and differentiation were assessed by non-competitive and competitive bone marrow transplantation. The potential effect of CTX on senescence of bone marrow hematopoietic cells was analyzed by detecting p16(Ink4a) mRNA relative expression and SA-β-galactosidase (gal) staining. The results showed that the CTX could induce long-term but latent damage to bone marrow hematopoietic cell function and lead to the decrease in competency of bone marrow hematopoietic cells to reconstitute while seemingly permitting a complete recovery. Furthermore, the serial-transplantation model showed that these mice received transplantation of bone marrow hematopoietic cells from CTX-treated mice exhibited a high expression of p16(Ink4a) mRNA and SA-β-gal staining. It is concluded that CTX-induced bone marrow cellular senescence may play an important role in CTX-induced long-term injury to bone marrow hematopoietic cells.
Animals ; Bone Marrow Cells ; cytology ; drug effects ; Cell Differentiation ; drug effects ; Cellular Senescence ; drug effects ; Cyclophosphamide ; adverse effects ; Hematopoiesis ; drug effects ; Mice ; Mice, Inbred C57BL

OBJECTIVETo observe the effect and mechanism of ginsenoside Rg1 in inducing senescence human leukemia K562 cell line.

METHODProliferation of K562 cell line induced by Rg1 was detected by MTT colorimetric test for the purpose to screen optimal active concentration and time (20 micromol x L(-1) , 48 h). Impact of Rg1 on cell cycle was analyzed using flow cytometry. The percentage of staining positive cells was detected by SA-beta-Gal staining. The expressions of senescence-related genes such as p16, p53, p21, Rb, were detected by RT-PCR and the changes in ultramicro-morphology were observed by transmission electron microscopy.

RESULTRg1 can significantly inhibit the proliferation of K562 cells in vitro and arrest the cells in G2/M phase. The percentage of positive cells stained by SA-beta-Gal was dramatically increased (P < 0.05) and the expression of cell senescence-related genes were up-regulated. The observation of ultrastructure showed that cell volume increase, heterochromatin condensation and fragmentation, mitochondrial volume increase, lysosomes increase in size and number.

CONCLUSIONRg1 can induce the senescence of leukemia cell line K562 and play an important role in regulating p53-p21-Rb, p16-Rb cell signaling pathway.

Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cellular Senescence ; drug effects ; Ginsenosides ; pharmacology ; Humans ; K562 Cells ; Leukemia ; drug therapy ; metabolism ; physiopathology ; Signal Transduction ; drug effects

The effect of the calcium ion (Ca2+) on the growth and differentiation of the mouse epidermal keratinocytes cultured in serum-free medium was investigated. It was found that the optimal level of calcium ion in the medium was about 0.2 mmol/L. Under such a culture condition the colony forming efficiency, attachment percentage, percentage of the cells with cornified envelops, and percentage of the senesced cells were measured to be about 10.8%, 30.8%, 5.1%, and 26.8%, respectively. However, the Ca2+ concentrations in the medium above 0.6 mmol/L resulted in significant differentiation and senescence of the keratinocytes, which was found to be harmful for keratinocyte growth and expansion in vitro.
Animals ; Calcium ; pharmacology ; Cell Adhesion ; drug effects ; Cell Differentiation ; Cell Division ; drug effects ; Cells, Cultured ; Cellular Senescence ; drug effects ; Epidermis ; cytology ; Keratinocytes ; cytology ; drug effects ; Mice

OBJECTIVETo study the effect of H2O2 on the morphological pattern,vitality,proliferation,cycle period of rabbit intervertebral disc nucleus pulposus cells.

METHODSTen New Zealand white rabbits (2 to 3 kg, female) were used for isolating nucleus pulposus cells under sterilized condition. The culture solution with 15% FBS and DMEM/F12 (1:1) was applied for cell cultivation. After 90% cell fusion, the first generation was obtain and stimulated by H2O2 with different concentrations of 0 micromol/L (control group), 130 micromol/L,216 p.mol/L,360 Ipmol/L, 600 micromol/L,and 1000 micromol/L.

RESULTSCompared with the control group, there was little difference of the biological property (P>0.05) in 130 micromol/L and 216 micromol/L H202-treated groups. When the concentration of H2O2 attained 360 micromol/L, 600 micromol/L, and 1 000 micromol/L, the cells suffered aging,with increased cell vacuoles,decreased proliferation,and aging:related increase of 13-galactosidase dyeing. The cell cycle of many nucleus pulposus cells was blocked in G1 stage other than entering S stage. With increasing H2O2 concentrations, the aging degree was increased.

CONCLUSIONA certain concentration of H202 could induce early aging of nucleus pulposus cells,resulting in biological abnormalities of these cells.

Animals ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cellular Senescence ; drug effects ; Female ; Hydrogen Peroxide ; pharmacology ; Intervertebral Disc ; cytology ; drug effects ; Oxidative Stress ; Rabbits

This study aims to explore the effect of extract of Ginseng Radix et Rhizoma, Notoginseng Radix et Rhizoma, and Chuanxiong Rhizoma(hereinafter referred to as GNS) on the SIRT1-autophagy pathway of endothelial cell senescence induced by hydrogen peroxide(H_2O_2). To be specific, vascular endothelial cells were classified into the blank control group(control), model group(model), model + DMSO group(DMSO), resveratrol group(RESV), and GNS low-dose(GNS-L), medium-dose(GNS-M), and high-dose(GNS-H) groups. They were treated with H_2O_2 for senescence induction except the control. After intervention of cells in each group with corresponding drugs for 24 h, cell growth status was observed under an inverted microscope, and the formation of autophagosome under the transmission electron microscope. In addition, the changes of microtubule-associated protein 1 light chain 3β(LC3 B) were detected by immunofluorescence staining. The autophagy flux was tracked with the autophagy double-labeled adenovirus(mRFP-GFP-LC3) fusion protein. Dansylcadaverine(MDC) staining was employed to determine the autophagic vesicles, and Western blot the expression of sirtuin 1(SIRT1), ubiquitin-binding protein p62, and LC3Ⅱ. After H_2O_2 induction, cells demonstrated slow growth, decreased adhesion ability, raised number of SA-β-gal-stained blue ones, a certain number of autophagosomes with bilayer membrane and secondary lysosomes in the cytoplasm, and slight rise of autophagy flux level. Compared with the model group, GNS groups showed improved morphology, moderate adhesion ability, complete and smooth membrane, decreased SA-β-gal-stained blue cells, many autophagosomes, autophagic vesicles, and secondary lysosomes in the cytoplasm, increased autophagolysosomes, autophagy flux level, and fluorescence intensity of LC3 B and MDC, up-regulated expression of SIRT1 and LC3Ⅱ, and down-regulated expression of p62, suggesting the improvement of autophagy level. GNS can delay the senescence of vascular endothelial cells. After the intervention, the autophagy flux and related proteins SIRT1, LC3Ⅱand p62 changed significantly, and the autophagy level increased significantly. However, EX527 weakened the effect of Chinese medicine in delaying vascular senescence. GNS may delay the senescence of vascular endothelial cells through the SIRT1 autophagy pathway.
Autophagy ; Cells, Cultured ; Cellular Senescence ; Drugs, Chinese Herbal/pharmacology* ; Endothelial Cells/drug effects* ; Hydrogen Peroxide ; Panax/chemistry* ; Sirtuin 1/genetics*

The effect of antioxidants on the in vitro life span of mouse keratinocytes was investigated in this work. It was found that the life span of the keratinocytes cultured in the medium supplemented with antioxidants was extended significantly. The most beneficial antioxidant used in this work was the mercaptoethanol, followed by the catalase and SOD. However, the growth rates of keratinocytes in vitro under all the experimental conditions still declined with the culture time. It was also found that the antioxidants added in the medium were also helpful to enhance the keratinocyte colony formation. In addition, the aging kinetics of the mouse epidermal keratinocytes in vitro were analyzed, and finally the aging rate constants corresponding to antioxidants used were calculated.
Animals ; Antioxidants ; pharmacology ; Catalase ; pharmacology ; Cell Division ; drug effects ; Cells, Cultured ; Cellular Senescence ; drug effects ; Keratinocytes ; cytology ; drug effects ; Mercaptoethanol ; pharmacology ; Mice ; Superoxide Dismutase ; pharmacology

OBJECTIVETo investigate the effects of D-galactose (D-gal) on aging of rat marrow mesenchymal stem cells (MSCs) and its mechanism.

METHODSMSCs isolated from young (7 d) SD rats were randomly divided into four groups:control group, 1g/L, 10g/L and 50g/L D-gal treatment groups. In control group MSCs were cultured in DMEM containing 10% FBS for 48 h. In the D-gal treatment groups, MSCs were cultured in DMEM containing 10% FBS with 1g/L, 10g/L or 50g/L D-gal for 48 h. The senescence-associated changes were examined with SA-β-galactosidase (SA-β-gal) staining, the expressions of p53, p21 and p16 were detected by Western blot. The living and apoptotic cells were determined by AO/EB staining. Cell proliferation was detected by MTT assay. SOD activity was measured by xanthine oxidase method, and the MDA content was estimated with thiobarbituric acid (TBA) method.

RESULTSCompared to control group, the number of SA-β-gal positive cells and the expression of p53, p21 and p16 were significantly increased in the 10g/L and 50g/L D-gal treatment groups. The apoptosis rate in 50g/L D-gal group was significantly higher than that in control group (P<0.01). The proliferation of MSCs was decreased in the 10g/L and 50g/L D-gal groups compared to control group (P<0.05). After 10g/L and 50g/L D-gal treatment, SOD activity was significantly decreased (P<0.01), and MDA level was increased (P<0.01).

CONCLUSIONThe aging of MSCs can be induced by 10g/L and 50g/L D-gal, which may be associated with the elevated levels of oxidative stress.

Animals ; Apoptosis ; drug effects ; Cells, Cultured ; Cellular Senescence ; drug effects ; Galactose ; pharmacology ; Male ; Mesenchymal Stromal Cells ; drug effects ; physiology ; Oxidative Stress ; Rats ; Rats, Sprague-Dawley

BACKGROUNDPrevious studies have shown that resveratrol increases endothelial progenitor cell (EPC) numbers and functional activity. Increased EPC numbers and activity are associated with the inhibition of EPC senescence. In this study, we investigated the effect of resveratrol on the senescence of EPCs, leading to potentiation of cellular function.

METHODSEPCs were isolated from human peripheral blood and identified immunocytochemically. EPCs were incubated with resveratrol (1, 10, and 50 µmol/L) or control for specified times. After in vitro cultivation, acidic β-galactosidase staining revealed the extent of senescence in the cells. To gain further insight into the underlying mechanism of the effect of resveratrol, we measured telomerase activity using a polymerase chain reaction (PCR)-enzyme-linked immunosorbent assay (ELISA) technique. Furthermore, we measured the expression of human telomerase reverse transcriptase (hTERT) and the phosphorylation of Akt by immunoblotting.

RESULTSResveratrol dose-dependently inhibited the onset of EPC senescence in culture. Resveratrol also significantly increased telomerase activity. Interestingly, quantitative real-time PCR analysis demonstrated that resveratrol dose-dependently increased the expression of the catalytic subunit, hTERT, an effect that was significantly inhibited by pharmacological phosphatidylinositol 3-kinase (PI3-K) blockers (wortmannin). The expression of hTERT is regulated by the PI3-K/Akt pathway; therefore, we examined the effect of resveratrol on Akt activity in EPCs. Immunoblotting analysis revealed that resveratrol led to dose-dependent phosphorylation and activation of Akt in EPCs.

CONCLUSIONResveratrol delayed EPCs senescence in vitro, which may be dependent on telomerase activation.

Cells, Cultured ; Cellular Senescence ; drug effects ; Endothelial Cells ; cytology ; drug effects ; enzymology ; Humans ; Stem Cells ; cytology ; drug effects ; enzymology ; Stilbenes ; toxicity ; Telomerase ; metabolism

This study was aimed to investigate the method to cold-store platelets with uridine diphosphate galactose (UDP-Gal). Rabbit heart blood was prepared for concentrated platelet suspension to which UDP-Gal was added, and then stored for ten days in 4 degrees C refrigerator. Thereafter, platelet count, mean platelet volume (MPV), platelet distributing width (PDW), platelet aggregation function, platelet activity to urge coagulation including PF3aT and APCT and apoptosis were determined. Meanwhile, survival time in vivo was tested after cold-stored rabbit platelets labeled with Cr51 were transfused into rabbits. The results showed that there was not significant difference for Plt count, MPV, PDW, PF3aT and APCT between UDP-Gal cold-stored platelet group and fresh platelet group (P > 0.05). On the contrary, platelet count decreased significantly, MPV, PDW jumped and PF3aT and APCT went down in cold control group as compared with fresh platelet group (P < 0.01). Apoptosis increased in UDP-Gal cold-stored platelet group as compared with fresh platelet group (P < 0.05), but was significantly lower than that in cold control group (P < 0.01). Although PagT (inducing reagent: C-PG) decreased, it could still be above 50% of fresh platelet. Survival time in rabbit in vivo was close between UDP-Gal cold-stored platelet group and fresh platelet group (P < 0.05). Survival rate in seventy-two hours after transfusion in the fresh platelet group, UDP-Gal cold-stored platelet group and cold control group was 57.5% +/- 7.2%, 50.3% +/- 6.3% and 0.1% +/- 0.5% respectively. It is concluded that the UDP-Gal can well protect cold-stored rabbit platelets and prolong the survival time of cold-stored platelets in vivo.
Animals ; Blood Platelets ; Blood Preservation ; methods ; Cellular Senescence ; drug effects ; Cryopreservation ; methods ; Platelet Aggregation ; drug effects ; Rabbits ; Time Factors ; Uridine Diphosphate Galactose ; pharmacology