BACKGROUND:Pancreatic stem cells exhibit the capacities to division and high differentiation and can be successfully isolated and cultured in vitro. But how to perform effective in vitro proliferation remains to be solved. OBJECTIVE: To in vitro subculture mouse pancreatic stem cells under the condition of embryonic fibroblast feeder layers. DESIGN, TIME AND SETTING: A cytological, in vitro observation was performed at the Room for Cell Sterile Culture, School of Basic Medical Sciences, Guangxi Traditional Chinese Medical University between July 2007 and January 2008. MATERIALS: Twenty newborn Kunming mice of specific pathogen free and of either gender, as well as some 14-day-pregnant Kunming mice, were purchased from Laboratory Animal Center, Guangxi Traditional Chinese Medical University. METHODS: The pancreas were obtained from newborn Kunming mice and digested with V type collagenase. When tissue blocks that were not completely digested settled naturally, the cell suspension on the upper layer was collected and centrifuged. After supernatant removal and addition of serum-free low glucose dulbecco's modified eagle's medium containing keratinocyte growth factors and basic fibroblast growth factors, cell suspension was cultured in polylysine-treated 24-well plate. Mouse embryo was taken from 14-day-pregnant Kunming mouse. After head and internal organs removal, the body and four limbs were isolated and cultured for obtaining fibroblasts by trypsin digestion. Following density adjustment, cells were inoculated into a 24-well plate at a density of 5×108/L. After 3 passages, mitomycin C treatment was conducted to prepare embryonic fibroblast feeder layer. Pancreatic stem cells primarily cultured for 5 days were inoculated into feeder layer cells-containing 24-well plate at a density of 30 cells per square centimeter. When cells spread about 80% of the whole bottom, passage could be continued. MAIN OUTCOME MEASURES: Cell morphology was observed under an inverted microscope. After 48 hours of primary culture, cells were dyed with alkaline phosphatase(ALP), and Nestin expression was identified by immunohistochemistry. ALP, Nestin, pancreatic duodenal homeobox-1(PDX-1) detections were performed at 2, 3, 4, and 5 days after passage. RESULTS: Among the cells derived from pancreas by primary culture, some large, round cells with single nucleus could be found, which exhibited strong endochylema refraction and high karyoplasmic ratio, grew adhering to the wall, were immunoreactive for ALP and Nestin, and simultaneously showed strong division and proliferation capacity. Under the condition of mouse embryonic fibroblast feeder layer, pancreatic stem cells could be serially passaged to the third generation. Each generation of cells still maintained their properties including large, round appearance with single nucleus, high karyoplasmic ratio, and proliferative capability. At each time point after passage, the cells were positive for ALP and Nestin staining but negative for PDX-1 staining, and maintained undifferentiated state.CONCLUSION: After mitomycin treatment, mouse embryonic fibroblast feeder layer can secrete the factors that promote the growth of pancreatic stem cells but inhibit the self-differentiation. After in vitro serial passages, the third generation of pancreatic stem cells can maintain their properties including good growth characteristics, high proliferation capacity, and undifferentiated state.

BACKGROUND: To date, there is no report on the anti-hepatoma mechanism of Chinese herbal medicine targeting hepatocellular carcinoma stem cells; therefore, relevant research is necessary. OBJECTIVE: To observe the effect of baicalein on the expression of Decoy receptor 3 in hepatocellular carcinoma stem cells as well as the biological behavior of hepatocellular carcinoma stem cells after down-regulation of Decoy receptor 3.METHODS: Hepatocellular carcinoma stem cells were obtained from hepatocellular carcinoma cell lines (purchased from the Cell Bank, Chinese Academy of Sciences, Shanghai, China), cultured and passaged. The cells were cultured in the low-glucose DMEM containing nothing (control group), 200 (high-dose group), 100 (middle-dose group) or 50 μmol/L (low-dose group) baicalein. After treatment with baicalein, RT-PCR and western blot were used to detect the expression of decoy receptor 3 at mRNA and protein levels. Cell counting kit-8, flow cytometry, and Transwell assay were used to detect the proliferation, cell cycle distribution, apoptosis and migration of hepatocellular carcinoma stem cells. RESULTS AND CONCLUSION: Compared with the control group, high-dose baicalein could significantly down-regulated the expression of decoy receptor 3 mRNA and protein in hepatocellular carcinoma stem cells. High-dose baicalein was then confirmed to be the best concentration of action. Compared with the control group, in the high-dose baicalein group, the proliferation ability of hepatocellular carcinoma stem cells decreased significantly, the percentage of S-phase and G2-phase cells increased, while the percentage of G1-phase cells decreased (P < 0.05). Compared with the control group, in the high-dose baicalein group, the apoptotic rate of hepatocellular carcinoma stem cells increased significantly, while the migration ability decreased markedly. To conclude, high-dose baicalein can inhibit a series of biological behaviors of hepatocellular carcinoma stem cells by down-regulating the expression of Decoy receptor 3, which provides an experimental basis for clinical treatment of hepatocellular carcinoma with Decoy receptor 3 as the target and hepatocellular carcinoma stem cells as the object.

BACKGROUND: In vivo experiments have confirmed that fibroblast growth factor can effectively protect gentamicin-induced renal tubular epithelial cell injury, but the effect on the in vitro cultured cells is still rare. OBJECTIVE: To explore the mechanisms of basic fibroblast growth factor (bFGF) at different concentrations on preventing nephrotoxity mediated by genamicin on the primarily cultivated renal tubular epithelial cell models. METHODS: By use of enzyme and mesh screening, renal tubular epithelial cells were isolated from Kunming mice and purified, adjusting the cell concentration of 1×10~8/L, then cell suspension was moved to a 96-well culture plate and divided into different groups for culture: blank control group: normal culture; gentamicin group: 10, 30, 50 μL/hola (ie, 400, 1 200, 2 000 U/holes)arerecorded as G1, G2, G3; bFGF group: 20, 50, 80 μL/hole (ie, 90,225, 360 ng/hole) are recorded as B1, B2, B3; gentamicin plus bFGF intervention group: after adding bFGF 12 hours, then added gentamicin 12 hours, assigned into 9 dose subgroups, namely, G1B1, G1B2, G1B3, G2B1, G2B2, G2B3, G3B1, G3B2, G3B3, each subgroup contained four-hole complex. Cell morphology and quantity was observed. RESULTS AND CONCLUSION: Gentamicin showed a dose-dependent effect on the renal tubular epithelial cell injury, epithelial cells in the medium and high concentration groups exhibited shrinkage, rounded, swelling, poor adhesion, severely damaged cytoplasm and structural disorder. In the low concentration group, the number change of cells was not obvious, and fibroblasts began to appear; In the bFGF groups, cells were full, exhibited strong refraction, the cell number increased significantly, these manifestations were significant in 50 μL/hole concentration, and there was no significant difference compared with 80 μL/hore concentration; in case of gentamicin plus bFGF intervention, cells with low concentrations of gentamicin had no obvious damage to cells, which increased, the damaged cells collapse was reduced in the group of low concentration of gentamicin, cell shrinkage and poor adhesion were slightly relieved, high concentrations of bFGF intervention could yield to good cell morphology, but high concentrations of gentamicin caused cell swelling and necrosis of injury, which could not be improved by any concentrations of bFGF intervention. 50 μL/hole bFGF has antagonistic effect on the nephrotoxicity mediated by medium and low concentrations of gentamicin, but has no protection on high concentration of gentamicin-induced nephrotoxicity.

BACKGROUND: There is no effective method to identify liver cancer stem cells until now, which has become one of the major challenges in this field. OBJECTIVE: To explore a more effective and suitable way for the identification of liver cancer stem cells in hepatocellular carcinoma cell lines. METHODS: Firstly, the single cell separation technique was used to obtain single cells, which were seeded into 96-wel plates one by one. Secondly, cell sublines derived from single cell colonies (tumorigenic colonies) were selected and obtained. At last, the cells from these clones were transplanted into the forelimb armpits of nude mice to observe the tumorigenic ability. RESULTS AND CONCLUSION: The number of holes of single cells obtained was 371 by the single cell separation technique, and the success rate was 96.4%. According to the growth of cell clone, tumorigenic colonies were selected to be transplanted to the forelimb armpits of nude mice, and the tumor formation rate of the colonies was 100%. The identification model of single-cell-transplant-tumorigenic-test for liver cancer stem cells is confirmed to be preliminarily established, which lays the technology and methodological basis for the follow-up research.

BACKGROUND:Until now, little has been reported on establishment of pancreatic stem cell strains and lines,and the purification of pancreatic stem cells is difficult since the cell line establish rate is low.OBJECTIVE:To explore a more rational and effective technique of in vitro separation and continuous passage of pancreatic stem cells, with the hope to establish cell strains and even cell lines and to lay the foundation for the follow-up study of pancreatic stem cells in the treatment of diabetes.METHODS:Firstly, Percoll discontinuous density gradient centrifugation method was applied to separate the mouse pancreatic endocrine portion from the exocrine portion, then to obtain cell strains with highly proliferative ability and low differentiation from pancreatic endocrine portion-the islet. We used mouse embryonic fibroblasts treated with mitomycin C as a feeder layer, for in vitro continuous culture of islet-derived pancreatic stem cells under feeder layer conditions until they were transferred to the 30th passage to establish cell lines. Then pancreatic stem cell line derived from pancreatic islet was detected and identified by a series of tests including growth characteristic test, morphological observation, related molecular marker identification and differentiation characteristic identification.RESULTS AND CONCLUSION:In the continuous process of passage, pancreatic stem cells showed active proliferative ability, and maintained the typical morphological characteristics of stem cells and expression of pancreatic stem cell marker-Nestin. After induction, pancreatic stem cells showed insulin gene expression,reflecting their differentiation potential. Therefore, under the condition of feeder layer, the pancreatic stem cell line derived from Kunming mice was successfully established and the related identification was completed,which lays the foundation for the following research.

BACKGROUND: There is a great debate but little research addressing the cell suspension obtained from the digested mantle tissues can effective amplify and form pearl sac in vitro, thus producing pearl. OBJECTIVE: To establish an effective technique and method of in vitro separation and culture of mantle of the pearl oyster (Pinctada martensii), and to determine the optimal method of forming pearl sac with the intact structure and secretion function, thus producing pearl. DESIGN, TIME AND SETTING: Single sample observation was performed at the School of Basic Medicine, Guangxi Traditional Chinese Medical University, between August and December in 2008. MATERIALS: Pearl oyster (Pinctada martensii) aged 1.0 2.0 years, were offered by Yingpan Pearl Industrial Co., Ltd. Of Beihai City, China; the self-modified marine shellfish balanced salt solution; the self-prepared concha pteriae serum and concha pteriae body fluid; keratinocyte growth factor was purchased from Sigma, USA. METHODS: The mantle of pearl oyster (Pinctada martensii) was digested with 2.5 g/L trypsin, the harvested cells were cultured using M199 medium containing 10% fetal bovine serum and supplemented with 10 μg/L keratinocyte growth factor, 10% self-prepared concha pteriae serum and concha pteriae body fluid. The cultivation was performed for 30 days. MAIN OUTCOME MEASURES: Cell growth characteristics and growth state. RESULTS: The pearl mantle epithelial cells cultured in vitro were shown to proliferate rapidly, secrete productively, and the muscle cells showed a great proliferation, finally encapsulated the mantle epithelial cells to form pear sac with the intact structure and strong secretion function. CONCLUSION: Using the modified culture technology and culture system, the addition of keratinocyte growth factor can obtain the well growing and secreting pearl sac during in vitro culture of mantle cells.

Objective:To examine the possibility of the differentiation into islet-like cell clusters from the co-culture system of bone marrow mesenchymal stem cells (BMSCs) and islet cells.Methods:Rat BMSCs from the femur and tibia of Wistar rats were isolated and purified taken under aseptic conditions; the surface markers CD 44 and CD 90 expressions of BMSCs were detected by flow cytometry; and alizarin red staining and oil red O staining were used to identify the cells induced in the osteogenic direction and adipogenic direction, respectively. Rat islet cells from the pancreas of Wistar rats were isolated and purified; and dithiazone staining was performed for validation. The basal insulin level of the culture was detected by ELISA method. 5.6mmol/L (low glucose) and 25.0 mmol/L (high glucosa) glucose were added to the culture, respectively, and insulin release was detected by ELISA. 5-generation BMSCs and islet cells were collected and divided randomly into stem cell culture alone group (stem cell group), stem cell-islet co-culture group (co-culture group), and islet culture alone group (islet group). The morphological changes of BMSCs during co-culture were observed using an inverted phase contrast microscope; basal insulin secretion and insulin secretion stimulated by low and high glucose were tested by ELISA. Insulin protein expression in induced islet-like cell masses in co-culture group were detected by immunocytochemical staining. The ultrastructure of islet-like cells was observed by using transmission electron microscopy. Results:The positive rates of CD 44 and CD 90 were 99.48% and 99.50%, respectively; BMSCs were induced the formation of multiple calcium nodules outside the differentiation cells in the osteogenic direction, and many lipid droplets in the cytoplasm of differentiated cells in the adipogenic direction. Dithiazone staining showed that β cells in pancreatic islet were brown red and about 450 islets could be obtained per pancreas with a mean purity up to 80%. The insulin release in the low sugar group and the high sugar group were (7.105±1.551) mIU/ml and (20.231±1.592) mIU/ml, respectively, with a statistically significant difference ( P<0.05). It can be seen that local stem cells began to gather and grow upward into small clumps in the budding manner until finally forming a spherical islet-like cell cluster structure after 7 days of culture in the co-culture group. The basal insulin secretion in the stem cell group was <0.5 mIU/L. In the islet group, insulin secretion peaked on the 5th day and then gradually decreased to about 20% of the highest value on the 13th day. The insulin level of the co-culture group peaked on the 5th day, and the 13th day remained at about 40% of the peak level. There were statistically significant differences on basal insulin secretion on the 8th, 10th and 13th day between islet group and co-culture group (all P value >0.05). There was no statistically significant difference between the insulin release by islet in islet group under the stimulation of low and high sugar and that by islet-like cell cluster in co-culture group. There were a large number of brownish-yellow granules in the islet-like cell clusters after the co-culture for 14 days; and there were more secretory granules and coarse endoplasmic reticulum in the ultrastructure, showing more active protein secretion functions. Conclusions:The co-culture system of BMSCs and islet cells could induce BMSCs into differentiating into islet-like cell clusters, which can express insulin protein and had relatively mature function of insulin secretion.