Biological nerve conduit model with de-epithelialized human amniotic membrane and adipose-derived mesenchymal stem cell sheet for repair of peripheral nerve defects

In this study, a biological conduit, consisting of an adipocyte-derived mesenchymal stem cell (AdMSCs) sheet and amniotic membrane (AM), was designed for the reconstruction of peripheral nerve defects. To evaluate the effect of the produced conduit on neural regeneration, a 10-mm sciatic nerve defect was created in rats, and experiments were carried out on six groups, i.e., sham control group (SC), negative control group (NC), nerve autograft group (NG), the biological conduit (AdMSCs + AM) group, the commercial PGA tube conduit (PGA) group, and the conduit only consisting of AM (AM) group. The effects of different nerve repair methods on the peripheral nerve and gastrocnemius muscle were evaluated by functional, histological, and immunohistochemical tests. When the number of myelinated axons was compared between the groups of AdMSCs + AM and PGA, it was higher in the AdMSCs + AM group (p < 0.05). The percentage of gastrocnemius collagen bundle area of AdMSCs + AM group was found to be statistically lower than the PGA group (p < 0.05). The muscle fiber diameter of AdMSCs + AM group was lower than that of the NG group, but significantly higher than that of the PGA group and the AM group (p < 0.001). Muscle weight index was significantly higher in the AdMSCs + AM group compared to the PGA group (p < 0.05). It was observed that nerve regeneration was faster in the AdMSCs + AM group, and there was an earlier improvement in pin-prick score and sciatic functional index compared to the PGA group and the AM group. In conclusion, the biological conduit prepared from the AdMSCs sheet and AM is regarded as a new biological conduit that can be used as an alternative treatment method to nerve autograft in clinical applications.

Melatonin is effective in attenuating cisplatin-induced neurotoxicity

Cisplatin (Cis) is a chemotherapeutic agent that has many side effects. Neurotoxicity is one of the most important of these side effects. Oxidative stress and neuroinflammation are the best-known mechanisms in the pathogenesis of neurotoxicity development. In this study, we aimed to determine whether melatonin (Mel), with antioxidant and anti-inflammatory effects, is effective in preventing Cis-induced neurotoxicity. Forty-eight male Sprague-Dawley rats were divided into six groups (n = 8) as follows: control (0.9% NaCl), vehicle (5% ethanol), Cis (6 mg/kg), Cis (6 mg/kg) + vehicle (5% ethanol), Mel (20 mg/kg), and Cis (6 mg/kg) + Mel (20 mg/kg) groups. Cis was administered as a single dose on the 3rd day of the experiment while Mel was given for 5 days. All administrations were performed via intraperitoneal injection. After injections, T-maze, rotarod, and hot plate tests were performed to evaluate cognitive, motor, and sensory functions, respectively. Following sacrification oxidative stress markers, cholinergic function, and proinflammatory cytokines were studied from brain homogenates. Cis impaired cognitive function and motor performance in the Cis and Cis+Vehicle groups. The drug also increased oxidative stress in the brain. Mel significantly improved brain oxidant/antioxidant status and also decreased the overproduction of proinflammatory cytokines (superoxide dismutase activities in Cis+Vehicle and Cis+Mel groups: 104.55 ± 9.50 µU/mg protein vs. 150.13 ± 4.70 µU/mg protein, respectively, p < 0.05; tumor necrosis factor-α levels in Cis and Cis+Mel groups: 40 pg/ml vs. 20 pg/ml, respectively, p < 0.05). It seems that Mel can improve Cis neurotoxicity. For a more firm conclusion, further studies using Mel at different doses with larger groups should be performed.