ABSTRACT
There are two kinds of treatments on Alzheimer's disease (AD) rat by transplanting neural stem cells (NSCs),i.e.the replacing cell curing and the gene therapy.By replacing method,the AD rats showed signs of recovering to some extent on both histomorphology and behavior after transplanting NSCs into their brains.Transplanting NSCs along with the nerve nutrition factor (NTFs) showed better curative effects than NSCs transplantation alone.However,little is known about the molecular mechanism involving in the development of NSCs in vivo conditions.And the blindness of the treatment hindered the comparison of various affecting factors.The NSCs gene therapy is still in initial studying,with the effects of both cell replacement and gene therapy.This treatment genetically modified NSCs mainly by unitary nutrition fators such as nerve growth factor (NGF),brain-derived neurotrophic factor (BDNF),and glial cell line-derived neurotrophic factor (GDNF).And it was almost known nothing about the exogenous gene expression efficiency,the induce differentiation,the restore of function and security after genetically-modified NSCs transplanted into the AD rat brain.The detecting technology of NSCs transplanting curative effects of the AD rat is unitary at present.And the combined method is the developing trend,such as combining the immunohistochemical method with in vivo-tracking,and combining morphology index with the function index.
ABSTRACT
OBJECTIVE: To investigate the clinical application of tissue engineering for treating tendon injury.METHODS: A computer-based online search was conducted in Medline and China Academic Journals Database with the key words of "Biological material, Sinew mechanism heals" in both English and Chinese from 1974 to 2009. Relevant books were hand-retrieved.RESULTS: Scholars at home and abroad tried to investigate how to regulate cell proliferation, differentiation, and matrix synthesis by endogenous and exogenous growth factors so as to promote tendon repairing, relieve tendon adhesion, and decrease attenuation of biomechanical intensity. Tendon detect was mainly treated by autologous tendon transplantation,allogeneic tendon transplantation, artificial tendon transplantation, and tissue-engineered tendon transplantation. All those methods had both advantages and disadvantages. However, artificial biomaterial tendon has attracted much attention and it has been used for clinical application. Of course, there are still more problems to be solved, for example, source of tissue-engineered seed cells, immunological reaction of allogeneic tendon cells, specific mechanical intension, preparation and selection of degradable scaffold materials, correlation between cell and scaffold materials, and correlation between cell-material compound and peripheral tissues. With the development of tendon repairing and healing, single drug which was used to prevent tendon adhesion has developed into drug-barrier compound. Additionally, with the development of Chinese herb and molecular biological products, they not only inhibited exogenous healing, but also promote endogenous healing. Meanwhile, simple surgery has also developed into combined therapy.CONCLUSION: Although biomaterials for tendon repairing have achieved breakthrough in some respects, the results need also to be further studied.