Implantation Of Glialcell Line-derived Neurotrophic Factor-expressing Marrow Stromal Cells In A Rat Parkinson's Disease Model

Parkison's disease (PD) is characterized by a loss of dopaminergic neurons in the substantia nigra and clinical symptoms that include bradykinesia , tremor at rest, and cogwheel rigidity. Several in vivo strategies have been used to replace dopamine in the striatum of patients and in animal model of PD. Currently one of the most promising treatments for PD is neural replacement by transplantation of engineered stem cells.Therapeutic effects of stem cell-mediated are determined by two fators, namely target gene and donor cells. In our study, glial cell line-derived neurotrophic factor is choosen treat PD. GDNF is a member of TGF- P family, which is currently considered as one of the most effective factors to protect dopaminergic neurons from degeneration. Previous data showed GDNF could increase the number of DA neurons, which resulted in the improvement of clinical symptoms of PD. Therefore , we cloned the full length cDNA sequence of rat GDNF.As for the donor cell, a candidate cell should own the following characters, such as easy to obtain and grow rapidly, survive well in vivo, express the target gene stably and long-term, not elicit the immunoreaction. A wide variety of donor cells, such as fibroblasts, embryonic ventral midbrain cells, astrocytes, embryonic stem (ES) cells, adrenal medullary cells, and carotid body cells, have been used with variable degrees of success in animal models of PD and in parkinsonian patients. However, none of these cell therapies has proven yet to be fully satisfactory due to different biological, technical and ethical reasons. For instance, gliosis indcuced by fibroblasts-produced collagen, difficulty to manipulate astrocytes in culture, ethical and legal issues raised by the cells from human fetuses, all need to be solved by finding alternative cell sources suitable for neural replacement. Marrow stromal cells (MSCs), also known as mesenchymal stem cell or colony-forming units(CFU)fibroblastic, are multipotent stem-like cells. MSCs have the advantage in neural transplantation that they can be easily obtained and expanded in culture, survive and integrate well without eliciting host immune response when transplanted into the rat brain. Furthermore, there has been increasing evidence that MSCs are capable of differentiating into both mesenchymal and nonmesenchymal lineages, especially into neurons and astrocytes in vitro and in vivo. As a result, we suggest that MSCs is suitable for neural transplantation.To investigate the therapeutic effects of GDNF-expressing BMSC on Parkinson's Disease, we firstly transferred GDNF into BMSC. For PD model, built up by injecting 6-OHDA into the lateral SN of rat, GDNF-BMSC was stereoxically injected into the striatum of the lesion-side. 7,14,21,28 days after transplantation, APO-induced rotations were respectively observed. Expression of GDNF was detected by PCR and Western blot in mRNA, protein level. Immunical histochemistry was used to examine the variety of TH-positive cell. After transplantation, behavioral recovery was firstly observed in 7th day, which went on till 28day. Compared with control group, GDNF expression of graft group significantly increased in mRNA and protein level. Meanwhile, number of TH-cells is much more than that of control. Obviously, GDNF-BMSC can significantly improve the behavior of PD rat, which is one of the effective tools to treat PD.