title: Microencapsulated nerve growth factor-expressing NIH3T3 cells-incorporated tissue engineering skin: a preliminary study.
abstract: BACKGROUND
  In order to find a suitable carrier to deliver the product of gene transfection to improve the performance of bioengineered dermis, we used microencapsulation and gene transfection technology together for the first time and found that it was feasible.
  
  
  METHODS
  We used a recombinant nerve growth factor (pcDNA3.1+/NGF) to modify NIH3T3 cells genetically. Control of NIH3T3-NGF cells were encapsulated within microspheres composed of alginate-poly-L-lysine-alginate and cultivated in-vitro. The concentration of NGF released from the microencapsulated NIH3T3-NGF cells was confirmed using ELISA assay. We co-cultivated microencapsulated NIH3T3-NGF cells, NIH3T3 cells (control) with human keratinocytes and fibroblasts, and tested the percentage of cycle of these cells. The alkaline hydrolysis method was used to analyse the content of hydroxyproline (Hyp). Immunohistochemistry method was used to calculate the transformation efficiency from fibroblasts to myofibroblasts.
  
  
  RESULTS
  The concentration of NGF released from the microencapsulated NIH3T3-NGF cells lasted about six weeks in the supernatant of bioengineered dermis in-vitro. The proliferation of keratinocytes, as well as the concentration of Hyp in supernatant of fibroblasts, were promoted about three times. Transformation efficiency from fibroblasts to myofibroblasts was increased approximately two-fold because of the bio-effects of NGF. Two kinds of microencapsulations were seeded into collagen which contained human fibroblasts to form bioengineered skin. Microencapsulated NIH3T3-NGF cells formed a thicker dermis. The concentration of Hyp in the bioengineered skin which indicated the level of collagen synthesis was increased due to existing NGF.
  
  
  CONCLUSIONS
  Microencapsulated NIH3T3-NGF cells can be used to enhance performance of bioengineered dermis and it also can be deduced that other cytokines can be used to treat local wound areas.
authors.affiliation: Department of Plastic Surgery and Burns, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province 710038, China.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Hu
authors.forename: S Z
authors.initials: SZ
authors.lastname: Chen
authors.forename: Y
authors.initials: Y
authors.lastname: Jin
authors.forename: Y
authors.initials: Y
authors.lastname: Xiong
authors.forename: W
authors.initials: W
authors.lastname: Wang
authors.forename: X J
authors.initials: XJ
authors.lastname: Ma
authors.forename: M
authors.initials: M
authors.lastname: Song
mesh_terms: D000464:Alginates; D000818:Animals; D002467:Cell Nucleus / Q000235:genetics*; D004339:Drug Compounding; D005240:Feasibility Studies; D005347:Fibroblasts; D005786:Gene Expression Regulation / Q000235:genetics*; D018398:Homeodomain Proteins; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells / Q000502:physiology*; D020932:Nerve Growth Factor / Q000235:genetics*; D011107:Polylysine / Q000031:analogs & derivatives; D017475:Receptors, Nerve Growth Factor / Q000235:genetics*; D012038:Regeneration / Q000235:genetics*; D012879:Skin Physiological Phenomena; D023822:Tissue Engineering / Q000379:methods*; D014162:Transfection / Q000379:methods*
chemical_list: D000464:Alginates; D018398:Homeodomain Proteins; D017475:Receptors, Nerve Growth Factor; C051546:alginate-polylysine-alginate; D011107:Polylysine; D020932:Nerve Growth Factor