ABSTRACT
Peripheral nerve lesions are a challenge for neurosurgeons and different surgical repairing methods are applied for the treatment of this problem. This study was conducted to evaluate the poled polyvinelidene fluoride [PVDF] tube filled with nerve growth factor [NGF] and collagen gel as a substitute for nerve autograft. In this experimental study the left sciatic nerve was manipulated in 50 male Wistar rats and then the animals were divided randomly into five groups. In the epineural group the injured nerves were repaired by end to end suture. In the rats with autograft a 10 mm piece of sciatic nerve was rotated through 180 and sutured in the nerve gap. In the nerve guidance channel group [NGC], polarized piezoelectric PVDF tube containing NGF and collagen gel was replaced in the gap and in the axotomy group two nerve ends were hidden among muscles. The left sciatic nerve was exposed but not transected in the sham group. After two months L4-L6 segment neurons of spinal cord were studied histologically and by immunohistochemical and axonal DiI tracing. The collected data were analyzed by one way ANOVA, LSD and paired t-test. The mean number of Bax positive cells and labeled motor neurons increased significantly in axotomy and sham group respectively, compared to the other groups [P<0.05]. Also, the mean number of labeled motor neurons increased significantly in epinural group in comparison to the autograft and the NGC groups [P<0.05]. There was no significant difference in the mean number of the labeled neurons between the autograft and nerve guidance channel groups. The mean number of motor neurons in the left side showed a significant decrease in comparison to that of the right side [p<0.01]. The PVDF tube together with other therapies provided a favorable environment for nerve regeneration and could be used as a substitute for autograft in nerve injuries
ABSTRACT
Bone marrow stem cells [BMSCs] are a rich source of stem cells and may represent a valid alternative to neural or embryonic stem cells by replacing the autologous damaged tissues in neurodegenerative diseases. In this study, we attempted to devise a protocol for the induction of BMSCs into neuroepithelial-like cells [NELCs]. Rat BMSCs were isolated from the long bones of adult Sprague-Dawley rats. Their purity in the 4th passage was evaluated with fibronectin by immunocytochemistry, and the stemness marker Oct-4 was assessed by RT-PCR technique. The cells were expanded and induced in the induction stage. The BMSCs were incubated with either beta-mercaptoethanol [micro ME] [1 mM], dimethyl sulfoxide [DMSO] [2%] or biotylated hydroxyanisol or butylated hydroxyanisol [BHA] [200 micro M] in beta-MEM medium without fetal bovine serum [FBS]. They were washed with phosphate buffer saline [PBS] and proceeded to the 2nd phase of induction, where the induction medium was changed with beta-MEM and 15% FBS containing all-trans retinoic acid [RA] [1 micro M] [for 3 days]. Then, the expression of the markers was assessed with GFAP, nestin and neurofilament 68 antibodies, respectively and the expression of Oct-4 and NeuroD was evaluated by RT-PCR. The purity of the BMSCs at the 4th passage was more than 92%. The mRNA of Oct-4 was expressed in these cells. Induction of BMSCs by DMSO-RA could differentiate NELCs significantly more than beta ME-RA and BHA-RA. The transdifferentiation of NELCs was evaluated by nestin antibody and NeuroD mRNA expression; later markers expressed very low detectable level in BMSCs. But the differentiation of BMSCs into astrocytes was less in all of the experiment groups that is estimated GFAP antibody. The application of DMSO-RA can transdifferentiate BMSCs into NELCs in- vitro