Collagen Gel Group Research Articles

Application of Human Adipose Stem Cell (hADSC) in Collagen Gel on Rat Deep Dermal Burn

Human adipose derived stem cells (hADSC) is expected to be an efficient solution for healing deep-dermal burns that help in wound closure. This study used 20 male Sprague dawley rats. Each rat received three wounds with different treatments (control, hADSC in collagen gel and collagen gel). Wound closure was observed at day 7th, 14th, 21th and 28th (sacrificed day) macroscopically, wound areas were measured and collagen densities were evaluated. Reduction of wound area showed significant difference between hADSC in collagen gel group and control group (p 0.001) and between hADSC in collagen gel group and collagen gel group. The hADSC in collagen gel group had a higher collagen density compared to control and collagen gel group. Application of hADSC in bovine collagen gel in rat deep-dermal burn models provided faster and better wound healing compared with control and bovine collagen gel group.

EFFECT OF HUMAN ADIPOSE-DERIVED STEM CELL IN COLLAGEN GEL ON RELATIVE EXPRESSION LEVEL OF VASCULAR ENDOTHELIAL GROWTH FACTOR-A OF DEEP DERMAL BURN HEALING

Objectives: The objectives of this research was to measure the relative expression levels of vascular endothelial growth Factor-A (VEGF-A) in the deep dermal burns treated with human adipose-derived stem cell (hADSC) in collagen gel in each observational day (days 7, 14, 21, and 28).Methods: This study used 20 male Sprague Dawley rats, divided into four groups of observation days. Each rat received three burn injuries and then given different treatments (hADSC in collagen gel, collagen gel, and control). Deep dermal burn injury on the dorsal was made by placing a metal plate with 250°C for 15 s. Relative expression level of VEGF-A measurement with quantitative reverse transcription polymerase chain reaction.Results: On the 7th day, the relative expression level of VEGF-A in the wound treated with hADSC in collagen gel was significantly different from the scaffold collagen and control group (p<0.05), whereas the control and scaffold collagen group was not significantly different. The relative expression level of VEFG-A in wound treated with hADSC in collagen gel, collagen gel only, and control was (mean±standard error of the mean) 17.93±4.37, 7.54±2.63, and 5.44±1.59, respectively. On the next observation days, the result showed that the relative expression level of VEGF-A was not significantly different between the three treatments. The relative expression level of VEGF-A has decreases from day 7 to 28 days. The decrease of VEGF-A relative expression level hADSC in collagen gel group was significantly different on the 7th day to the 21st and 28th days (p<0.05).Conclusion: The provision of hADSC in scaffold collagen increases the relative expression of VEGF-A early in the wound healing process compared to the without a hADSC group.

Effect of controlled release of brain-derived neurotrophic factor and neurotrophin-3 from collagen gel on neural stem cells.

This study aimed to examine the effect of controlled release of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) from collagen gel on rat neural stem cells (NSCs). With three groups of collagen gel, BDNF/collagen gel, and NT-3/collagen gel as controls, BDNF and NT-3 were tested in the BDNF-NT-3/collagen gel group at different time points. The enzyme-linked immunosorbent assay results showed that BDNF and NT-3 were steadily released from collagen gels for 10 days. The cell viability test and the bromodeoxyuridine incorporation assay showed that BDNF-NT-3/collagen gel supported the survival and proliferation of NSCs. The results also showed that the length of processes was markedly longer and differentiation percentage from NSCs into neurons was much higher in the BDNF-NT-3/collagen gel group than those in the collagen gel, BDNF/collagen gel, and NT-3/collagen gel groups. These findings suggest that BDNF-NT-3/collagen gel could significantly improve the ability of NSCs proliferation and differentiation.

Reconstitution with Bone Marrow Cells is Consistently Defective in the Tibia of Aged Monkeys

Biological aging is associated with a progressive loss of regulation of cellular, tissue and organ interaction, ultimately resulting in senescence. Fat gradually occupies bone cavity with age. Studies of the hematopoietic system using nonhuman primates have provided important information for understanding the mechanism of human hematopoiesis. We previously reported that excellent reconstitution of donor hematopoietic cells in a collagen gel group was observed in the long term in mice. We therefore investigated whether the method would be helpful for reconstituting hematopoiesis in the fatty tibias of monkeys. Nine- to 11-year-old monkeys were used for this study to examine if hematopoiesis could be restored in the fatty marrow of old monkeys. Bone marrow cells were collected from the humerus using the perfusion method, mixed with cultured bone marrow mesenchymalstroma cells in collagen gel, and then injected into the tibia of the same monkey. Clot sections were made from the tibias 1, 2 and 6 weeks after the bone marrow transplantation. However, no bone marrow cells were observed at any of the time points. These results suggested that bone marrow reconstitution is consistently defective in aged monkeys.

Hemopoiesis Regulated Negatively In Aged Monkeys

Biological aging is associated with a progressive loss of regulation of cellular, tissue and organ interaction, ultimately resulting in senescence. In humans, accelerated marrow adipogenesis has been associated with aging and several chronic conditions, including diabetes mellitus and osteoporosis. Studies of the hemopoietic system using nonhuman primates have provided important information for understanding the mechanism of human hemopoiesis. Excellent reconstitution of donor hemopoietic cells in a collagen gel group has been observed in the long term in mice. We therefore investigated whether the method would be helpful for reconstituting hemopoiesis in the fatty tibias of monkeys. Nine- to 11-year-old monkeys were used for this study to examine if hemopoiesis could be restored in the fatty marrow of old monkeys. Bone marrow cells were collected from the humerus using the perfusion method, mixed with cultured bone marrow stroma cells in collagen gel, and then injected into the tibia of the same monkey. Clot sections were made from the tibias 1, 2 and 6 weeks after the bone marrow transplantation. However, no bone marrow cells were observed at any of the time points. These results suggested that adipocytes negatively regulate bone marrow reconstitution. Disclosures: No relevant conflicts of interest to declare.

Growth and differentiation of neural stem cells in a three-dimensional collagen gel scaffold.

Collagen protein is an ideal scaffold material for the transplantation of neural stem cells. In this study, rat neural stem cells were seeded into a three-dimensional collagen gel scaffold, with suspension cultured neural stem cells being used as a control group. Neural stem cells, which were cultured in medium containing epidermal growth factor and basic fibroblast growth factor, actively expanded and formed neurospheres in both culture groups. In serum-free medium conditions, the processes extended from neurospheres in the collagen gel group were much longer than those in the suspension culture group. Immunofluorescence staining showed that neurospheres cultured in collagen gels were stained positive for nestin and differentiated cells were stained positive for the neuronal marker βIII-tubulin, the astrocytic marker glial fibrillary acidic protein and the oligodendrocytic marker 2’,3’-cyclic nucleotide 3’-phosphodiesterase. Compared with neurospheres cultured in suspension, the differentiation potential of neural stem cells cultured in collagen gels increased, with the formation of neurons at an early stage. Our results show that the three-dimensional collagen gel culture system is superior to suspension culture in the proliferation, differentiation and process outgrowth of neural stem cells.

Intra-Bone Marrow Injection of Donor Bone Marrow Cells Suspended in Collagen Gel Retains Injected Cells in Bone Marrow, Resulting in Rapid Hemopoietic Recovery in Mice

We have recently developed an innovative bone marrow transplantation (BMT) method, intra-bone marrow (IBM)-BMT, in which donor bone marrow cells (BMCs) are injected directly into the recipient bone marrow (BM), resulting in the rapid recovery of donor hemopoiesis and permitting a reduction in radiation doses as a pretreatment for BMT. However, even with this IBM injection, some of the injected BMCs were found to enter into circulation. Therefore, we attempted to modify the method to allow the efficient retention of injected BMCs in the donor BM. The BMCs of enhanced green fluorescent protein transgenic mice (C57BL/6 background) were suspended in collagen gel (CG) or phosphate-buffered saline (PBS), and these cells were then injected into the BM of irradiated C57BL/6 mice. The numbers of retained donor cells in the injected BM, the day 12 colony-forming units of spleen (CFU-S) counts, and the reconstitution of donor cells after IBM-BMT were compared between the CG and PBS groups. The number of transplanted cells detected in the injected BM in the CG group was significantly higher than that in the PBS group. We next carried out CFU-S assays. The spleens of mice in the CG group showed heavier spleen weight and considerably higher CFU-S counts than in the PBS group. Excellent reconstitution of donor hemopoietic cells in the CG group was observed in the long term (>100 days). These results suggest that the IBM injection of BMCs suspended in CG is superior to the injection of BMCs suspended in PBS.

Glial cell line-derived neurotrophic factor enhances axonal regeneration following sciatic nerve transection in adult rats

Adult rat sciatic nerve was transected and sutured with an entubulation technique. The nerve interstump gap was filled with either collagen gel (COL) or collagen gel mixed with glial cell line-derived neurotrophic factor (COL/GDNF). Four weeks after nerve transection, horseradish peroxidase (HRP)-labelled spinal cord motoneurons and the myelinated distal stump axons were quantified. Compared with the COL group, the percentages of labeled spinal somas and axon number were significantly increased after topically applied glial cell line-derived neurotrophic factor (GDNF). The functional recovery of the transected nerve was improved in COL/GDNF group. GAP-43 expression was also significantly higher in COL/GDNF group 1 and 2 weeks after sciatic nerve axotomy vs. COL group. These data provide strong evidence that GDNF could promote axonal regeneration in adult rats, suggesting the potential use of GDNF in therapeutic approaches to peripheral nerve injury and neuropathies.