Investigation of Therapeutic Efficacy of Olfactory Mucosal Mesenchymal Stem Cells in Peripheral Nerve Injury
Project no. 31851 · Status: Kapanmış (Yayın bekleniyor) · 2023
Summary
<p>Olfactory ensheathing cells (OECs), glial cells located in the lamina propria of the olfactory mucosa, continue the process of neurogenesis throughout life to protect against environmental damage and ensure the continuity of olfactory sensation. It has been reported that these stem cells, found in both olfactory nerve axons and the olfactory bulb, can produce not only olfactory neurons</p><p>but also other cells of the olfactory epithelium. Due to their high differentiation potential, OECs possess characteristics similar to mesenchymal stem cells and have potential applications in regenerative therapies. In this thesis study, the therapeutic and regenerative potentials of OECs were investigated for the first time by using them as a cellular therapy agent in a rat model of</p><p>femoral nerve injury.</p><p>OECs were cultured in vitro. Wistar albino rats with experimental femoral nerve injury were divided into three groups: the C group (control, no surgical intervention), the S group (surgical control, surgery performed), and the OEC group (experimental group, surgery performed, and OEC transplantation conducted). On the 7th, 14th, and 21st days after the operation, the animals</p><p>were subjected to grid walking tests, footprint tests, and five-toe spread tests to evaluate the regularity of their movements and the recovery of neural functions. On the 28th day post-operation, all subjects were sacrificed under anesthesia. Femoral nerve samples were collected for histopathological and molecular biological tests. The samples for histopathological evaluation were fixed in a mixture of 2% glutaraldehyde and 2% paraformaldehyde in 0.2 M PBS buffer. Samples for molecular biological evaluation were washed with saline and stored at -80°C in a deep freezer. Samples undergoing electron microscopic examination were embedded in epon. Semi-thin sections of 1 µm thickness were taken, and epon and osmium acid were removed. Histochemical staining with H&E and Toluidine Blue was performed, and immunohistochemical labeling with anti-GFAP, anti-p75NGF, anti-CNTF, and anti-Nestin was carried out. Molecular biological analysis was performed using RT-qPCR to analyze the BDNF, NT-3, NT-4, and NGF genes as</p><p>proteins localized in the extracellular space of the cells applied to the experimental groups. All data were statistically evaluated.</p><p><br></p><p>In the Five-Toe Spread test, the C group showed normal toe spread, while the OEC group showed improvement in toe spread each week, and the S group consistently exhibited abnormalities in toe spread parameters. In the grid walking test, the foot error index in the OEC group significantly decreased over time compared to the S group, while the measurements in the C group remained</p><p>the same on the three different days. In the footprint test, no significant difference was observed in the C group, whereas the OEC group showed a significant improvement in femoral function index over time compared to the S group, which had higher values.</p><p>Histopathological evaluation revealed thickening of the perineurium, increased endoneurium, axonal edema, degeneration of myelin, and various conformational abnormalities and separations in the S group. In the OEC group, the perineurium was found to be similar to that of the C group, axonal edema was minimized, and myelin degeneration had ceased. Axon diameter, myelin, and</p><p>perineurium thickness were measured and statistically evaluated in all groups. Immunohistochemically, Nestin expression was observed only in the OEC group. p75NGF expression was highest in the OEC group, while the fewest GFAP-positive cells were observed in the S group. CNTF expression was highest in the OEC group. RT-PCR results showed that, in addition to neurotrophic factors such as BDNF and NGF, both NT-3 and NT-4 were secreted in the OEC transplantation area.</p><p>All these factors are thought to accelerate axonal regeneration and help neurons recover more quickly. It was observed that in rats transplanted with OECs after femoral nerve injury, there was improvement in all parameters of tests indicating the recovery of femoral nerve function. In conclusion, it was observed that the acute and local application of high-dose OECs on day 0 in partially transected femoral nerve injuries had positive effects on nerve regeneration.</p>