There is evidence from other studies that some degree of cartilage healing may take place after the initiation of an inflammatory response. It is postulated that the induction of the platelet-cartilage interaction may eventuate in cartilage repair. The treatment of fresh articular cartilage with proteolytic enzymes rendered the tissue active as a platelet aggregant. During platelet aggregation a host of active substances are released which are known to play a role in the inflammatory response (Thompson 1975). This study was undertaken to evaluate the effects of trypsin on the surface injury of rabbit hyaline cartilage. The results were as follows: 1) Hyaline cell regeneration was observed only in the group treated with trypsin and blood; 2) Hyaline cartilage regeneration did not occur in the group treated with a single injection of trypsin or blood; 3) There was no significant damage to the healthy articular cartilage by the single injection of trypsin or blood, or both; and 4) Platelets do not adhere to cartilage and superficial damaged cartilage does not induce platelet aggregation.
Animal ; Cartilage, Articular/*drug effects/physiology/ultrastructure ; Cell Division ; Mitosis/physiology ; Platelet Aggregation/drug effects ; Rabbits ; Regeneration ; Trypsin/*pharmacology ; Wound Healing/drug effects/physiology

Neuronal PC12 cells induced by nerve growth factor (NGF) have been considered to be postmitotic and lack the ability to divide. However, in this study, we not only detected DNA synthesis but also observed cell division in some morphologically differentiated neuronal PC12 cells bearing long neurites. More interestingly, in addition to the division of perikaryon, the neurites located on the division site of the cell membrane also divided into two parts and were allocated to the two daughter cells. These results demonstrate that the morphologically differentiated neuronal PC12 cells still retain the ability to divide. This is the first report that neuronal PC12 cells as well as their neurites can divide.
Animals ; Cell Differentiation ; drug effects ; Cell Division ; drug effects ; DNA Replication ; drug effects ; physiology ; Nerve Growth Factor ; pharmacology ; Neurites ; drug effects ; Neurons ; cytology ; PC12 Cells ; Rats

In order to elucidate the effect of acetylcholine (ACh) on the occurrence and development of human pituitary adenoma, it was firstly observed whether there exists choline acetyl transferase (ChAT) which is necessary for the synthesis of acetylcholine in the cells of human pituitary adenoma, and then MTT method, (3)H TdR incorporation, cell cycle analysis and TUNEL were employed to estimate the influence of ACh on the proliferation, DNA synthesis and apoptosis of three kinds of human pituitary adenoma (human prolactinoma, somatotropinoma and non-functional tumor) cells cultured in vitro. The results showed that (1) the positive staining of ChAT was obviously observed in the cells of the three kinds of human pituitary adenoma, however, it was lower than that in normal human pituitary gland; (2) ACh had a similar effect on the proliferation of the three kinds of human pituitary adenoma cells. ACh at 0.1-10 micromol/L decreased the (3)H TdR incorporation and the MTT A value in a dose-dependent manner. At the same time, ACh decreased the ratio of S or G(2) phase pituitary adenoma cells significantly, but increased the ratio of G(1) phase pituitary tumour cells markedly; (3) the effect of acetylcholine on the proliferation of human pituitary adenoma cells was inhibited by atropine, but not by tubocurarine; (4) ACh had no effect on the apoptosis of human pituitary adenoma cells cultured in vitro. These data suggest that ACh may have a significant modulating effect on the proliferation of pituitary adenoma cells by means of paracrine or autocrine, and the effect is mediated by muscarinic receptor.
Acetylcholine ; pharmacology ; physiology ; Acetyltransferases ; biosynthesis ; physiology ; Adenoma ; pathology ; secretion ; Apoptosis ; drug effects ; Cell Division ; drug effects ; Dose-Response Relationship, Drug ; Humans ; Pituitary Neoplasms ; pathology ; secretion ; Tumor Cells, Cultured

OBJECTIVETo investigate the effects of Ginsenoside Rb(1) on the proliferation of Schwann cells in culture.

METHODSApplying MTT assay and Thymidine incorporation assay, the effects of Ginsenoside Rb(1) on the proliferation of Schwann cells isolated from the sciatic nerve of adult rat were studied.

RESULTSGinsenoside Rb(1) (10 microg/ml) significantly induced Schwann cell proliferation, the effect was similar to NGF (50 microg/ml). At high concentrations of Ginsenoside Rb(1) (1 mg/ml), the proliferation of Schwann cells was significantly inhibited.

CONCLUSIONSGinsenoside Rb(1) at the optimal concentrations is found to be effective in inducing the proliferation of Schwann cells, but at higher concentrations the drug is cytotoxic for Schwann cells.

Animals ; Cell Division ; drug effects ; physiology ; Cells, Cultured ; Dose-Response Relationship, Drug ; Ginsenosides ; adverse effects ; pharmacology ; Immunohistochemistry ; Nerve Regeneration ; drug effects ; Probability ; Rats ; Rats, Inbred Strains ; Schwann Cells ; drug effects ; physiology ; Sciatic Nerve ; cytology ; physiology ; Sensitivity and Specificity

OBJECTIVETo evaluate the effect of enamel matrix protein (EMP) on the attachment and proliferation of periodontal ligament cells (PDLC) on diseased cementum surfaces in vitro.

METHODSCementum chips were obtained from diseased roots exposed to periodontal pocket. Thirteen diseased root cementum chips were conditioned with EMP. Meanwhile, 13 diseased and 13 healthy cementum chips were treated with physiological saline as control. The growth and morphology of PDLC on the root surface were observed after 24 hours incubation by scanning electron microscope (SEM). PDLC attachment and proliferation were quantified using MTT assay at 16 or 72 hours.

RESULTSThe cells on EMP treated roots under SEM were growing robust like the cells on healthy roots. By contrast, the diseased cementum surface without conditioned with EMP was only partly covered with spindle-shaped cells, with filopodia appearing short and thin. MTT assay indicated that the number of adhered and proliferated cells on diseased cementum chips treated with EMP was significantly greater than that on diseased chips treated with saline (adhesion: 0.45 +/- 0.03 vs. 0.37 +/- 0.05, P < 0.05; proliferation: 0.71 +/- 0.02 vs. 0.55 +/- 0.08, P < 0.01), but less than that on healthy chips (adhesion: 0.45 +/- 0.03 vs. 0.67 +/- 0.08, P < 0.05; proliferation: 0.71 +/- 0.02 vs. 1.05 +/- 0.09, P < 0.05).

CONCLUSIONSIt was suggested that EMP could promote the growth of PDLC on the diseased root cementum surface.

Cell Adhesion ; drug effects ; Cell Division ; drug effects ; Cells, Cultured ; Dental Cementum ; physiology ; Dental Enamel Proteins ; pharmacology ; Humans ; Microscopy, Electron, Scanning ; Periodontal Ligament ; cytology ; Periodontitis ; pathology

OBJECTIVETo study the effects of emodin on proliferation and differentiation of 3T3-L1 preadipocyte and the possible mechanism.

METHODSCell proliferation was determined by MTT spectrophotometry, cell differentiation was determined by Oil Red O staining,and fatty acid synthase (FAS) activity was determined by spectrophotometry.

RESULTSEmodin promoted proliferation of 3T3-L1 preadipocyte at low concentration and inhibited the proliferation at high concentration in a dose-related manner. In contrast, it inhibited cell differentiation into adipocyte at low concentration in a dose-related manner. In vitro emodin inhibited the activity of FAS in a dose-related manner.

CONCLUSIONSThe effects of emodin on 3T3-L1 cell's proliferation and differentiation are dose dependent. Emodin inhibits the activity of FAS. Our results suggest that emodin should have a potential to serve as a fat-reducing drug.

3T3 Cells ; Adipocytes ; drug effects ; physiology ; Animals ; Cell Differentiation ; drug effects ; Cell Division ; drug effects ; Emodin ; pharmacology ; Fatty Acid Synthases ; antagonists & inhibitors ; Lipid Metabolism ; Mice ; Stem Cells ; drug effects ; physiology

Intravenous immunoglobulin (IVIG) is being increasingly used to treat numerous immune-mediated diseases. However, there is a paucity of knowledge on the specific mode of action of IVIG in vivo. In this study, the in vitro effects of IVIG on peripheral blood mononuclear cell (PBMC) proliferation using phytohemagglutinin (PHA), anti-CD3 monoclonal antibody (MAb), phorbol myristate acetate (PMA), or purified protein derivatives (PPD) have been analyzed. The PBMCs were obtained from more than 10 individual donors. In all cases, IVIG almost completely inhibited PBMC proliferation at concentration above 20 mg/mL except when used in conjunction with PMA. PHA-induced proliferation of PBMCs at concentrations ranging from 1 to 15 mg/mL did not show significant differences. Anti-CD3 MAb-induced proliferation showed dose-dependent inhibition at concentrations ranging from 1 to 10 mg/mL. Interestingly, PMA-induced proliferation of PBMCs showed a dose-dependent increase at the same concentration range. PPD-induced proliferation of PBMC at concentrations ranging from 1 to 10 mg/mL did not show any statistically significant differences. These results suggest that high dose IVIG may be necessary to immune modulation in vivo and IVIG has various effects on PBMCs proliferation in limited concentration in vitro.
Cell Division/drug effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Human ; Immunoglobulins, Intravenous/*pharmacology ; Leukocytes, Mononuclear/*drug effects/physiology ; Tetradecanoylphorbol Acetate/pharmacology

OBJECTIVETo investigate the effect of the basic fibroblast growth factor (b-FGF) to regenerate an autologous tissue-engineered cartilage in vitro.

METHODSThe Cells were harvested from the elastic auricular cartilage of swine,and were plated at the concentration of 1 x 10(4) cells/cm2 , studied in vitro at two different media enviroments: Group I contained Ham's F-12 with supplements and b-FGF, Group II contained Ham's F-12 only with supplements. The passage 2 cells (after 12.75 +/- 1.26 days) were harvested and mixed with 30% pluronic F-127/Ham's F-12 at the concentration of 50 x 10(6) cells/ml. It was injected subcutaneously at 0.5 ml per implant. The implants were harvested 8 weeks after the vivo culture and examined with the histological stains.

RESULTSThe chondrocytes displayed morphologically similar to the fibroblasts in the media containing basic-FGF. The number of cell doublings (after 12.75 +/- 1.26 days) in vitro culture was as the following: Group I, 70; Group II, 5.4. Eight 8 weeks after the vivo autologous implantation, the average weight (g) and volume (cm3) in each group was as the following: Group I, 0.371 g/0.370 cm3 Group II, 0.179 g/0.173 cm3 (P < 0.01). With the b-FGF in vitro culture, the cells were expanded by 70 times after 2 weeks. Histologically, all of the engineered cartilage in the two groups were similar to the native elastic cartilage.

CONCLUSIONThese results indicate that the basic-FGF could be used positively to enhance the quality and quantity of the seeding cells for the generation of the well-engineered cartilage.

Animals ; Cartilage ; cytology ; drug effects ; physiology ; Cell Division ; drug effects ; Cells, Cultured ; Chondrocytes ; cytology ; drug effects ; Female ; Fibroblast Growth Factors ; pharmacology ; physiology ; Male ; Regeneration ; drug effects ; Swine ; Tissue Engineering ; methods ; Transplantation, Autologous

OBJECTIVETo investigate the expression of inducible heme oxygenase (HO-1) gene in pulmonary artery smooth muscle cells (PASMCs) exposed to hypoxia, and the influence of carbon monoxide (CO) on the proliferation of PASMCs under hypoxic conditions.

METHODSPrimary culture of rat PASMCs were passed every 3 days, and the 3 - 5 passages were used. After exposure to hypoxic conditions (95% N2, 5% CO(2)) 0, 12, 24 and 48 hours, the level of HO-1 mRNA was examined by reverse transcriptase polymerase chain reaction (RT-PCR). The volume of COHb in the medium was measured spectrophotometrically. The cyclic guanosine mono-phosphate (cGMP) concentration of cell extracts was determined by radioimmunoassay. PASMCs were divided into 5 groups, cultured under normoxia and hypoxia and treated with hemin, hemoglobin (Hb) and exogenous CO respectively. Then 3-(4, 5-cimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) colorimetric assay and immunocytochemical staining were used to study the energy metabolism and the expression of proliferating cell nuclear antigen (PCNA) in PASMCs. Flow cytometry was used to analyze the cell cycle of PASMCs.

RESULTSAfter exposure to hypoxic conditions for 12, 24, and 48 hours, the HO-1 mRNA increased by 2.7%, 5.7% and 27.1% respectively (P < 0.01). The carboxy-hemoglobin (COHb) in the medium increased by 13.8%, 31.0% and 93.1% (P < 0.01); the cGMP concentrations were 2.7, 4.0 and 6.8-fold compared with the control group (P < 0.01 and P < 0.05). In comparison with the control group, the value of MTT colorimetric assay, the immunocytochemical staining of PCNA and the percentages of PASMCs in S and G2M phases in the hypoxic group were significantly higher (P < 0.01). After treatment with Hemin and CO, the results of the above analysis decreased significantly (P < 0.01 and P < 0.05), but increased significantly after treatment with Hb (P < 0.01 and P < 0.05).

CONCLUSIONSThe expression of HO-1 gene in PASMCs is upregulated by hypoxia and the production of endogenous CO is elevated as well. The endogenous CO suppresses the proliferation of PASMC in an autocrine way. Both the induction of endogenous CO by Hemin and the treatment with exogenous CO can suppress the proliferation of rat PASMCs of under hypoxic conditions.

Carbon Monoxide ; pharmacology ; physiology ; Cell Division ; drug effects ; Cells, Cultured ; Gene Expression ; Heme Oxygenase (Decyclizing) ; genetics ; Hypoxia ; pathology ; Myocytes, Smooth Muscle ; cytology ; drug effects ; pathology ; Pulmonary Artery ; pathology

UNLABELLEDIn this study, the roles of hematopoietic inhibitors elaborated by bone marrow endothelial cells in the proliferation and differentiation of hematopoietic progenitors were investigated. Murine bone marrow endothelial cell conditioned medium (BMEC-CM) was collected and the components with > 10 kD and < 10 kD were obtained by centrifugal ultrafiltration. The effect of BMEC-CM and its components on proliferation of hematopoietic progenitors was evaluated by CFU-GM and HPP-CFC assay and antibody neutralization test. The expression of the inhibitors in BMEC and BMEC-CM was detected by RT-PCR and Western blot, and change of proliferation and differentiation-related genes during expansion of hematopoietic progenitors was examined by membrane hybridization technique.

THE RESULTS(1) When BME C-CM and its components directly were added to CFU-GM and HPP-CFC culture system, BMEC-CM had no effect on colony formation, > 10 kD component enhanced and < 10 kD component inhibited the formation of CFU-GM and HPP-CFC. (2) When BMEC-C M and its components were added to liquid culture system of marrow cells, after 24 hours incubation, CFU-GM decreased and HPP-CFC increased significantly in B MEC-CM group, CFU-GM increased and HPP-CFC had no significant change in > 10 kD component group; and both CFU-GM and HPP-CFC reduced in < 10 kD group. (3) MIP-2, MIP-1 alpha, MSP, TGF-beta, TNF-alpha, IFN-gamma and T beta 4 were expressed in murine marrow endothelial cells, and MIP-2, MIP-1 alpha, MSP, TGF-beta, TNF-alpha and T beta 4 were existed in BMEC-CM. (4) Antibody neutralization test results demonstrated that TGF-beta, MSP, MIP-1 alpha, IFN-gamma and T beta 4 existed in BMEC-CM had significant suppressive effects on CFU-GM and HPP-CFC. (5) T beta 4 combined with 5 hematopoietic cytokines (SCF, IL-3, IL-6, GM-CSF and EPO) added to CD34(+) cells expansion culture system, HPP-CFC significantly increased compared with 5 cytokines group. T beta 4 could downregulated the expression of proliferation and differentiation-related genes and signal transduction-related genes. It is concluded that BM EC-CM promotes the proliferation of early hematopoietic progenitor cells, and this effect is related with the inhibitors existed in BMEC-CM and it could be executed via influencing cell proliferation and differentiation-related genes and signal-related genes.

Animals ; Bone Marrow Cells ; metabolism ; Cell Division ; drug effects ; Cytokines ; genetics ; pharmacology ; Endothelium ; cytology ; metabolism ; Hematopoietic Stem Cells ; drug effects ; physiology ; Mice ; RNA, Messenger ; analysis ; Thymosin ; pharmacology