poly-L Research Articles

A novel lacrimal duct prosthesis and its biodegradation and biocompatibility

Background The primary management for nasolacrimal duct obstruction is the combination of lacrimal duct probing with lacrimal duct stent implantation.However, conventional implant is undegradable.New degradable lacrimal duct prosthesis based on biopolymer materials is a research hotspot. Objective This study described herein a preparation method of novel degradable lacrimal duct prosthesis and its application. Methods A new degradable lacrimal tube stent was prepared with compound of poly L lactic acid (PLLA) and polycaprolactone (PCL) (6∶4) and 15% polyethylene glycol (PEG). Thirty-two Japanese rabbits aged 3-4 months were randomized into postoperative 1-week group, postoperative 4-week group, postoperative 8-week group and postoperative 16-week group.The degradable lacrimal tube stents were inserted into the lacrimal ducts of the left eyes of the rabbits.The prosthesis was removed in corresponding time points according to grouping, and the integrity and weight of the prosthesis were evaluated.The mucosal findings of the operative eyes were examined under the endoscope, and the histopathological and inflammatory reaction was observed by hematoxylin & eosin stain.The ultrastructure of the lacrimal mucosal surface was examined under the scanning electron microscope.The use and care of the rabbits complied with the Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission. Results The new degradable PLLA: PCL+ 15%PEG lacrimal duct stents were smooth, flexible and hydrophilic tubes.The removed tubes were intact in the postoperative 1-week group, however, the rupture of the tubes appeared in the postoperative 4-week group, while discrete pieces of the tubes were seen in the postoperative 16-week group.The weight-loss rates of the tubes were (13.44±6.59)%, (23.96±6.33)%, (55.08±6.55)% and (78.00±8.74)% in the postoperative 1-week group, postoperative 4-week group, postoperative 8-week group and postoperative 16-week group, respectively, and the weight-loss rate of the tubes was significantly higher in the postoperative 16-week group than those in the postoperative 8-week group (q=4.27, P 0.05). The edema, hyperemia and mild proliferation of the lacrimal mucosal were exhibited in the eyes of the postoperative 4- and 8-week groups, and the mucosal findings were almost normal in the eyes of the postoperative 16-week group under the endoscope.Histopathological examination showed a large number of inflammatory cells in the postoperative 1-, 4- and 8-week groups.However, few inflammatory cells were seen in the postoperative 16-week group.Mucosal folds, microvillus decrease and disorder were displayed in the lacrimal duct of the postoperative 8-week group, and no evident abnormality was seen in the lacrimal duct mucosal surface.No postoperative complication occurred in all the rabbits. Conclusions PLLA: PCL+ 15%PEG lacrimal duct stent has an appropriate degradation speed and good biocompatibility after implant in rabbits, and its decay period of mechanical strength could match lacrimal duct healing period. Key words: Lacrimal duct; Stents; Polymers/chemistry; Biodegradability; Biocompatibility; Lacrimal duct obstruction/therapy; Rabbits, Japanese

Modified poly L acid-type collagen I loaded with bone marrow mesenchymal stem cell for diabetic wound of rat

Objective To investigate the effect of modified poly L acid-type collagen I loaded with bone marrow mesenchymal stem cell （BMSCs） for diabetic wound of rat. Methods 36 diabetic rats were randomly divided into 3 groups： A （poly L acid-type collagen I ＋ BMSCs）, B （poly L acid-type collagen I） and C （ control）, the wound healing was observed and the cytokeratin in 5-BrdU BMSCs was detected. Re- suits The wound healing rate in 3, 5, 7, 14 d of group A were （18. 20 ± 2. 68 ） % , （30.60±5.50）%, （57. 63 ±9. 13）%, （87. 35 ±5. 83 ）% respectively and faster than group B （P 〈 0. 05） and group C （ P 〈 0. 05 ） , the newly-grown skin in group A had more blood vessel, cutaneous appendages and thicker than group B and group C, the cytokeratin were detected in the 5-BrdU BMSCs. Conclusion Modified poly L acid-type collagen I loaded with BMSCs can promote the rat diabetic wound healing. Key words: Bone marrow mesenchymal stem cells; Diabetic wound

Growth inhibition and apoptosis of a multiple myeloma cell line induced by TLR3 pathway activation

Objective To investigate the roles of TLR3 pathway activiated by polyI:C in proliferation and apoptosis of multiple myeloma (MM) RPMI8226 cell line.Methods RPMI8226 cells were cultured in RPMI 1640 with different dose of polyl:C.Cells were collected in different time.Proliferation and apoptosis were detected by CCK-8 kit and flow cytometry,separately.Results The proliferation of RPM18226 was inhibited by polyI:C,and it was dose and time dependent,24 h:12.30％ ±2.04％,22.50％±2.20％,37.90％ ±1.30％ ; 48 h:17.80％ ±1.52％,29.60％ ±0.85％,45.80％ ±1.68％ ;72 h:25.10％±1.01％,34.60％±1.27％,60.50％±2.08％,P＜0.05.RPMI8226 cells were incubated with 50 μg/ml,100 μg/ml and 200 μg/ml polyI:C for 48 h.Apoptotic rate were 5.60％ ±1.06％,8.71％ ±1.06％ and 13.93％ ±1.17％,P＜0.05.TLR3 and TRIF mRNA expression increased obviously and dose dependent,TLR3:1.41±0.10,2.24±0.16,4.08±0.13; TRIF:1.07±0.16,1.97±0.13,3.56±0.19,P＜0.05.Conclusion The proliferation of MM cells were inhibited by TLR3 pathway obviously,and apoptosis was induced by polyI:C. Key words: Multiple myeloma; Toll like receptor 3 ; Proliferation; Apoptosis; PolyI : C

Alginate polylysine microcapsules as immune barrier: Permeability of cytokines and immunoglobulins over the capsule membrane

Transplantation of pancreatic islets in alginate polylysine microcapsules is a potential useful method for treating type I diabetes. In this study, the permeability for alginate-polylysine microcapsules to cytokines an immunoglobulines has been investigated by a newly developed method. Magnetic monodisperse polymer particles (Dynabeads) coated with antibodies against selected proteins were encapsulated in 0.7 mm alginate polylysine microcapsules. The capsule membrane permeability to IgG (150 kDa), Transferrin (81 kDa), Tumor necrosis factor (TNF, 51 kDa), Interleukin-1β (IL-1β, 17.5 kDa), and insulin (5.8 kDa) was estimated by measuring the binding of 125I-labeled proteins to the encapsulated antibody coated Dynabeads. Capsules with an inhomogeneous solid gel core were made of alginates with high guluronic or high mannuronic acid content and poly- l (PLL)- or poly- d-lysine (PDL) of concentrations varied from 0.05–0.2%. The various capsules examined were all impermeable to IgG. The capsules made with a PLL-, but not PDL-membranes were permeable for transferrin. IL-1β was found to penetrate all of the different capsule types. The high-G capsules, however, could be made impermeable to TNF and still allowed transferrin to pass. The permeability of these capsules to IL-1β, but not to TNF was confirmed in an assay where mouse islets of Langerhans were incubated with TNF and IL-1β, and comparing the IL-6 for encapsulated and nonencapsulated islets.

Alginate polylysine microcapsules as immune barrier: permeability of cytokines and immunoglobulins over the capsule membrane.

Transplantation of pancreatic islets in alginate polylysine microcapsules is a potential useful method for treating type I diabetes. In this study, the permeability for alginate-polylysine microcapsules to cytokines an immunoglobulines has been investigated by a newly developed method. Magnetic monodisperse polymer particles (Dynabeads) coated with antibodies against selected proteins were encapsulated in 0.7 mm alginate polylysine microcapsules. The capsule membrane permeability to IgG (150 kDa), Transferrin (81 kDa), Tumor necrosis factor (TNF, 51 kDa), Interleukin-1 beta (IL-1 beta, 17.5 kDa), and insulin (5.8 kDa) was estimated by measuring the binding of 125I-labeled proteins to the encapsulated antibody coated Dynabeads. Capsules with an inhomogeneous solid gel core were made of alginates with high guluronic or high mannuronic acid content and poly-L (PLL)- or poly-D-lysine (PDL) of concentrations varied from 0.05-0.2%. The various capsules examined were all impermeable to IgG. The capsules made with a PLL-, but not PDL-membranes were permeable for transferrin. IL-1 beta was found to penetrate all of the different capsule types. The high-G capsules, however, could be made impermeable to TNF and still allowed transferrin to pass. The permeability of these capsules to IL-1 beta, but not to TNF was confirmed in an assay where mouse islets of Langerhans were incubated with TNF and IL-1 beta, and comparing the IL-6 for encapsulated and non-encapsulated islets.