Objective To review the common methods of isolation and purification of porcine islets and research progress. Methods Domestic and abroad literature concerning the isolation and purification of porcine islets was reviewed and analyzed thoroughly. Results The efficacy of the isolation and purification depends on the selection of donor, the procurement and cryopreservation of high-quality donor pancreas, and the selection and improvement of the operation. Conclusion The shortage of transplanted islets could be resolved by the establishment of standardized and optimal process, which may also promote the development of porcine islet xenograft.
Objective The purity and activity of islets will greatly affect the outcome of xenotransplantation therapy of type 1 diabetes mell itus. To set up an improved method of the isolation and purification of rat islets, which can obtain highpurity,high-yield, and high-viabil ity islets. Methods Ten healthy and adult male SD rats, weighing 250-300 g were used asorgan donors. Collagenase V was perfused into pancreas via pancreatic duct. Pancreas was digested with collagenase in water bath at 38℃ about 15 minutes, islet purification was performed using two techniques: with Ficoll 400 density gradient (group A), and Ficoll-Paque™ PLUS (group B). Dithizone (DTZ) was util ized for identifying islets, counting islets equivalent quantity (IEQ) and islets’ purity. Trypan blue staining was used to detect the viabil ity of islets. Islets of group B was encapsulated with alginate/poly-L-lysine/alginate (APA). Islets function of microencapsulated and nonmicroencapsulated was evaluated by the insul in release test. Results DTZ staining showed that islets shape were round, ell ipse and irregular with a clear edge and a diameter range of 50-300 μm. The IEQ values were 338.04 ± 76.61 and 834.80 ± 54.00 in groups A and B, respectively, showing significant difference (P lt; 0.05). The purities were 88.31% ± 2.67% and 95.63% ± 1.96% in groups A and B, respectively, showing no significant difference (P gt; 0.05). The activities of islets were 67.40% ± 5.15% and 86.05% ± 2.52% in groups A and B, showing significant difference (P lt; 0.05). Islet APA microcapsules had round shape, unified size, and its diameter was between 1.5 and 2.0 mm. Each microcapsule was encapsulated of 1 to 3 islets. The result of insul in release assay was that the concentrations of insul in secretion with islets of microencapsulated and nonmicroencapsulated were (5.53 ± 1.64) ng/ mL and (4.76 ± 0.26) ng/mL in low glucose, and its concentrations of insul in secretion in high glucose were (11.95 ± 2.07) ng/ mL and (14.34 ± 3.18) ng/mL. Stimulated insul in secretion in high glucose was 2 times more than that in low glucose (P lt; 0.05), but there was no significant difference (P gt; 0.05) in the stimulation index between group A (2.16 ± 0.30) and group B (3.01 ± 0.59). Conclusion The method of islets isolation and purification using Ficoll-Paque™ PLUS own the virtues of more convenient, high islet yield, and high islet purity. Both microencapsulated and nonmicroencapsulated islets show high-viabil ity while culture in vitro.
Objective To review the general approaches in isolation and purification of pancreatic islets and progress in several aspects. Methods The latest l iterature concerning acquisition of pancreatic islets was reviewed and analyzed interms of the choice of pancreatic islet donors, the digestion and isolation of pancreas, the purification of islet and the assay of outcome. Results The profile of the isolation and purification depends on the selection of reagents and methods of operation in every step and l inkup between every step. Conclusion Pancreatic islet transplantation is the most effective method to treat type 1 diabetes, the problem of inadequate sources of pancreatic islets could be resolved by the optimal process and the establ ishment of standardized operation.
【Abstract】 Objective To explore good methods for isolation and purification of rat islets. Methods The isletswere isolated from male SD rat pancreata by a collagenase perfusion method and purified by a modified method: added 4 kinds of Euro-Ficoll of different densities (F1: D=1.132, F2: D=1.108, F4: D=1.069, F5: D=1.023), discontinuous density gradient centrifuge the tube at 2 000 r/min for 20 minutes at 4℃ , then the islets between F1 and F2 were collected. The purity of islets was assessed by dithizone staining with islets counted and scored for size. Islets viabil ity was assessed by fluorescin diacetate / propidium iodide. The function of purified islets was judged by the test of insul in release and islets transplantation. Results After an improved method for optimized isolation and purification, (920±122) IEQ purified islets were obtained from one rat. Both the purity and viabil ity of islets were over 90%. The amount of insul in secretion was (18.25±0.32) mU/L and (36.70±3.57) mU/Lat 2.2 mmol/ L and 22.2 mmol/L concentration of glucose respectively, there was significant difference between the two phases(P lt; 0.05). The insul in release index was 2.01±0.15. Under 1 000 IEQ islets transplantation, the normal glucose level could beremained in diabetic rats. Conclusion High purity and high viabil ity islet cells can be got through improved collagenase perfusion and centrifugation on gradients method.
To set up an economic and effective method for islet isolation from rat, and thereby prove a laboratory protocol of animal model for cl inical islet transplantation. Methods Twenty-five adult male SD rats weighing 230-380 g were used as organ donor. In each of 5 repeated experiments, pancreatic islets of 5 animals were isolated by intraductal infusion of compound sodium chloride injection (CSCI), and subsequently, digested with low concentration (0.5 mg/mL)of collagenase V solution. Islet purification was performed by using a discontinuous density gradient centrifugation thatwas prepared with 27.0%, 23.0%, 20.5% and 11.0% of Ficoll 400. Islet yield and purity were determined by dithizon (DTZ)stain, and propidium iodide (PI)/fluorescein diacetate (FDA) double stain was used to check viabil ity of islets. The endocrine secretory function was assessed by insul in secretion in either low (2.8 mmol/L) or high (25.0 mmol/L) glucose incubation after 3 days of culture in RPMI1640 media. Results Average islet digestion time of 5 experiments was (13.8 ± 1.6) min. Before purification, average isolated number was (5 626 ± 422) islets, and the number was significantly reduced to (2 914 ± 485) islets after purification (P lt; 0.01). The average recovery rate was 51.6% ± 6.0%, and the average yield was (583 ± 97) islets/pancreas. The average purity and viabil ity of islets were 90.2% ± 3.4% and 81.6% ± 7.0%, respectively. After 3 days of culture, insul in secretion of the islets was (116.1 ± 17.4) EU/L in high glucose incubation, which was significantly higher than that of low glucose environment [(39.7 ± 7.5) EU/L, P lt; 0.01)]. The average insul in stimulation index was 3.0 ± 0.4. Conclusion The islet isolation with the CSCI solution and digestion with low concentration of collagenase V decrease experimental cost and also have a beneficial effect on islet recovery and their function.
Objective To explore the isolating methods of rat submandibular gland cell for primary culture. Methods Rat submandibular gland cell were isolated by direct isolation and pancreatin digestion respectively, and then were cultured and subcultured on DMEM. The shape and structure of cultured cells were observed with phase contrast microscope. The cell survival rate was detected by using trypan blue elimination test. The vital force of culture cells was estimated with MTT colorimetric method. The cultured cell secretion function was evaluated by assay of amylase activity. Results By direct isolatin, the cell survival rate was 70% and the cell vital force was 0.16±0.014. By pancreatin digestion, the cell survival rate was 85% and the cell vital force was 0.45±0.13; the cells had good shape and attached well. The Ck8.13 and keratin antibodies were epithelium specific and α-SMA antibodies were myoepithelium specific. The cells were stained positively with CK8.13, keratin and α-SMA antibodies. Conclusion The method of pancreatin digestion for the isolation of submandibular gland cell is better than that of idrect isolation.
Objective To find effective ways for controlling the hospital infection to the skeptical gas gangrene patients. Method From May 14th to June 24th, the hospital set up triage spots originally and dealt with the wounded based on their specific conditions in different stages and optimized the flow of admission of the wounded. Owing to correctly treating the wound and screening the skeptical gas gangrene patients, preventing nosocomial infections was shifted forward. Sprending the gas gangrene wound after having flushed it with 3% H2O2. If the wound have been stitched, the stitches should bee taken out, and open the wound and take the debridement for it completely, then treat it with b antibacterial after debridement by sterilization and isolation about operation of gas gangrene. Result Up to June 24th, none of 67 cases of doubtful gas gangrene from the disaster area died and no hospital cross infections happened in courtyard. At present, amomg the 67 cases, 32 were highly suspected of gas gangrene infection, 26 cases were discharged, while 6 cases were undergoing treatment in the hospital. Conclusion Correct management and appropriate treatment are effective ways for controlling hospital cross infection to the skeptical gas gangrene patients.
Objective To explore the proper dosage of establishment of stable hepatic oval cells （HOC） prolif-eration model by using 2-acetaminofluorene （2-AAF） combined with two-third partial hepatectomy （2/3 PH） surgery， and to explore isolated and cultured method of HOC in vitro. Methods The 174 Wistar rats were randomly divided into 4 experimental groups （each group enrolled 30 rats）， saline group （n=30）， and untreated group （n=24）. Rats of 4 experi-mental groups were underwent gavage of 5， 10， 15， and 20 mg/（kg ? d） 2-AAF， corresponding to the groups from No.1 to No.4 group. Rats of saline group received saline gavage and rats of untreated group didn’t received any treatment. A standard 2/3 PH surgery was performed on the 5th day after gavage， then the same gavage method was still administrated as preoperation untill rats were sacrificed. The liver tissues of 6 selected rats were adopted and identified by HE staining and immunohistochemical staining on 4， 8， 12， and 16 days after PH for observation of the proliferation of HOC in every group， on 4 days， levels of alanine aminotransferase （ALT） and aspartate aminotransferase （AST） were tested in addition. HOC were isolated and purified by collagenase perfusion method and percoll gradient centrifugation. Results The surv-ival rates of untreated group，saline group，No.1 group，No.2 group，No.3 group，and No.4 group were 100% （24/24），93% （28/30），93% （28/30），90% （27/30），90% （27/30），and 80% （24/30） respectively. Compared with the saline group and untreated group， the levels of serum ALT and AST increased significantly in No.2， No.3， and No.4 group on the 4th day after PH （P＜0.05）. The results of HE staining showed that No.2， No.3， and No.4 group were observed visibly different level of damage at liver tissue， and the proliferation level of HOC were most obviously in No.3 and No.4 group. The results of immunohistochemical staining revealed that proliferation cells were positively expressed oval cell marker-6 （OV-6）. The number of OV-6 positive cells were increased significantly with the increase of dosage of 2-AAF between 4 days and 12 days after operation， and proliferation levels were related with dosages of 2-AAF （P＜0.05）. In all cultured cells， 80% of cells were OV-6 positive cells after isolation and culture by using collagenase perfusion method and percoll gradient centrifugation. Conclusions The methods of gavage of 2-AAF at 15 mg/（kg ? d） combined with 2/3 PH surgery can establish the HOC proliferation model on the 12th day， as well as the rats have lower mortality and better tolerance， especially. The collagenase perfusion method and percoll gradient centrifugation can be used to isolate HOC effectively.
ObjectiveTo obtain the mesenchymal stem cells (MSCs) from human umbilical cord and mark in vitro, for further transplantation therapy. MethodsThe MSC were isolated from human umbilical cord by tissue explants culture method. After subculture in vitro, the morphology of hUC-MSC was observed; the surface antigens of hUC-MSC were detected by flow cytometry; adipogenic and osteogenic differentiation were determined by specific staining; hUC-MSC labelled with Brd U were identified by immunofluorescence. ResultsMSC could be isolated successfully by tissue explants culture method. When cultured about one week, the cells climbed out from the tissue block edge, proliferated and formed colonies; the hUC-MSCs of passage 5 were detected by flow cytometry, and they highly expressed CD73, CD90 and CD105, didn't express or lowly expressed CD14, CD34, CD45, CD79a and human leukocyte antigen-DR. After two weeks of adipogenic induction, they were positive in oil red O staining, and after three weeks of osteogenic induction, red precipitate could be seen by alizarin red staining, and the red fluorescence of the hUC-MSC labelled with Brd U could be detected by immunofluorescence detection. ConclusionThe cells can be isolated from human umbilical cord by tissue explants culture method, with the characteristics of hUC-MSCs and can be labeled successfully in vitro, so it can be used for the research in the field of cell transplantation.
ObjectiveTo provide theoretical and technological support for further study of liver metabolism and disease by comparing the advantages and disadvantages of various artificial liver models (biological). MethodsLiteratures were searched and compared to summarize the requirement for liver donor, isolation, and culture of hepatocyte. ResultsIn the separation method of hepatocyte, mechanical separation method had no requirement for liver donor, and was easy to acquire hepatocyte, while the acquired hepatocyte would be destructed severely, and the survival rate was low. On the other hand, the restriction of the digestion of the hepatocytes to the liver cell samples was unlimited, while the key of the enzyme digestion method was to regulate the balance between enzyme concentration and digestion time, which was limited to function researches of hepatocyte, and research about the responds of hepatocyte against outside, and other few researches. Perfusion digestion method had been widely applied for animal test. The Ca2+, collagenase and perfusion rate, pH value, buffer, and intubation method all play vital roles. During the cultivation, we needed to choose different methods according to several experiments, and add different additives in the appropriate medium. Different biological reactors had different advantages, disadvantages, and applicable conditions. ConclusionsThe donor selection is based on various experimental purposes to harvest hepatocytes from different sources. Whether on the separation process or on the cultivation process, according to the specific circumstances, such as the concentration, perfusion time, and the choice of different kinds of culture medium, we can choose different kinds of bioreactors, but all kinds of methods are still remained with multiple insufficiencies, which require more researchers to improve.