BACKGROUND: Based on recent advances in tissue engineering and stem cell therapy in nervous system diseases treatments, this study aimed to investigate sciatic nerve regeneration using human endometrial stem cells (hEnSCs) encapsulated fibrin gel containing chitosan nanoparticle loaded by insulin (Ins-CPs). Stem cells and also Insulin (Ins), which is a strong signaling molecule in peripheral nerve regeneration, play an important role in neural tissue engineering.
METHODS: The fibrin hydrogel scaffold containing insulin loaded chitosan particles was synthesized and characterized. Release profiles of insulin from hydrogel was determined through UV-visible spectroscopy. Also, human endometrial stem cells encapsulated in hydrogel and its cell biocompatibility were assigned. Furthermore, the sciatic nerve crush injury was carried out and prepared fibrin gel was injected at the crush injury site by an 18-gage needle. Eight and twelve weeks later, the recovery of motor and sensory function and histopathological evaluation were assessed.
RESULTS: The in vitro experiments showed that the insulin can promote hEnSCs proliferation within a certain concentration range. Animals\' treatment confirmed that developed fibrin gel containing Ins-CPs and hEnSCs significantly improves motor function and sensory recovery. Hematoxylin and Eosin (H&E) images provided from cross-sectional and, longitudinal-sections of the harvested regenerative nerve showed that regenerative nerve fibers had been formed and accompanied with new blood vessels in the fibrin/insulin/hEnSCs group.
CONCLUSIONS: Our results demonstrated that the prepared hydrogel scaffolds containing insulin nanoparticles and hEnSCs could be considered as a potential biomaterial aimed at regeneration of sciatic nerves.

OBJECTIVE: To evaluate the efficacy of a perineural injection of dexmedetomidine combined with ropivacaine for reducing postoperative methadone requirements in dogs after tibial plateau levelling osteotomy (TPLO).
METHODS: A prospective, clinical, randomized and blinded trial.
METHODS: A total of 58 client-owned dogs.
METHODS: Ultrasound-guided midfemoral sciatic and inguinal femoral nerve blocks with ropivacaine (1 mg kg-1 per nerve block) combined with either dexmedetomidine (0.5 μg kg-1 per nerve block; group DEX) or the same volume of saline (group CON) were performed in dogs undergoing TPLO. Pain was assessed 30 minutes, 2 hours and then every 4 hours for 24 hours after surgery with a validated pain scale (4AVet). Meloxicam (0.15 mg kg-1) was administered intravenously (IV) at recovery. Rescue methadone (0.2 mg kg-1 IV) was administered if a score ≥ 6 (maximal score 18) was recorded and the number of postoperative doses was analysed by Fisher exact tests. The study was performed in parallel at a Veterinary Teaching Hospital (VTH) and a private Veterinary Referral Centre (VRC).
RESULTS: Dogs received a total of 22 and 31 postoperative doses of methadone in groups DEX (14 doses at VRC, eight doses at VTH) and CON (28 doses at VRC, three doses at VTH), respectively. Overall, there was no difference in the postoperative rescue analgesia requirements between groups (p = 0.244). At the VRC, dogs received less methadone (p = 0.026) in group DEX compared with group CON, whereas at the VTH, there was no difference between groups (p = 0.216).
CONCLUSIONS: Perineural dexmedetomidine combined with ropivacaine did not reduce postoperative methadone requirements in dogs after TPLO, but results may differ from one centre to another. This discrepancy might be linked to variations in clinical practices and questions the validity of results obtained from single-centre randomized controlled trials but applied to different clinical settings.

Purpose: The improvement of techniques using conduits that connects the ends of damaged nerves and guides the growth of nerve fibers between the stumps, including adoption of natural or synthetic materials still is a challenge in peripheral nerve repair. The aim of the present novel study was to fabricate and transplant chitosan-selenium biodegradable nanocomposite conduit on transected sciatic nerve in rat model.Methods: In NORMAL group, the left sciatic nerve was exposed through a gluteal muscle incision and after careful hemostasis skin was closed. In TRANSECTED group left sciatic nerve was transected and stumps were fixed in adjacent muscle. In CHITOSAN and CSBNC groups, 10-mm sciatic nerve defects were bridged using a chitosan and chitosan-selenium biodegradable nanocomposite conduits, respectively. The regenerated fibers were studied 4, 8 and 12 weeks after surgery. Assessment of nerve regeneration was based on behavioral, functional, biomechanical, histomorphometric and immunohistochemical criteria.Results: The behavioral, functional and biomechanical studies confirmed significant recovery of regenerated axons in CSBNC group (P < 0.05). Quantitative morphometric analyses of regenerated fibers showed the number and diameter of myelinated fibers in CSBNC group were significantly higher than in the CHITOSAN group (P < 0.05).Discussion: This demonstrates the potential of using CSBNC in peripheral nerve regeneration without limitations of donor-site morbidity associated with isolation autograft. It is also cost saving and may have clinical implications for the surgical management of patients after facial nerve transection.

OBJECTIVE: To assess regenerative capacities of chitosan-nanoselenium conduit on transected sciatic nerve in diabetic rats.
METHODS: A 10-mm sciatic nerve defect was bridged using a chitosan-nanoselenium conduit filled with phosphate buffered saline. In chitosan group, the chitosan conduit was filled with phosphate buffered saline solution. In sham-operated group, sciatic nerve was exposed and closed. In transected group, right sciatic nerve was transected and nerve cut ends were fixed in the adjacent muscle. The regenerated fibers were studied within 12 weeks after surgery.
RESULTS: The behavioral and functional and electrophysiological tests confirmed faster recovery of the regenerated axons in chitosan-nanoselenium conduit group compared to chitosan group (p=0.001). The mean ratios of gastrocnemius muscles weight were measured. There was statistically significant difference between the muscle weight ratios of chitosan-nanoselenium conduit and chitosan groups (p=0.001). Morphometric indices of regenerated fibers showed number and diameter of the myelinated fibers were significantly higher in chitosan-nanoselenium conduit group than in chitosan group.
CONCLUSIONS: chitosan-nanoselenium conduit resulted in acceleration of functional recovery and quantitative morphometric indices of sciatic nerve.

UNASSIGNED: To determine the effects of chitosan-zinc oxide nanocomposite conduit on transected sciatic nerve in animal model of rat.
UNASSIGNED: Sixty male White Wistar rats were used in this study. A 10-mm sciatic nerve defect was bridged using a chitosan-zinc oxide nanocomposite conduit (CZON) filled with phosphate buffered saline. In chitosan group (CHIT) the chitosan conduit was filled with phosphate buffered saline solution. In sham-operated group (SHAM), sciatic nerve was exposed and manipulated. In transected group (TC), left sciatic nerve was transected and nerve cut ends were fixed in the adjacent muscle. The regenerated fibers were studied within 12 weeks after surgery.
UNASSIGNED: The behavioral and functional tests confirmed faster recovery of the regenerated axons in CZON group compared to Chitosan group (p<0.05). The mean ratios of gastrocnemius muscles weight were measured. There was statistically significant difference between the muscle weight ratios of CZON and Chitosan groups (p<0.05). Morphometric indices of regenerated fibers showed number and diameter of the myelinated fibers were significantly higher in CZON than in Chitosan. In immuohistochemistry, the location of reactions to S-100 in CZON was clearly more positive than Chitosan group.
UNASSIGNED: Chitosan-zinc oxide nanocomposite conduit resulted in acceleration of functional recovery and quantitative morphometric indices of sciatic nerve.

OBJECTIVE: To determine the effects of local administration of platelet rich plasma (PRP) on peripheral nerve regeneration in rat sciatic nerve transection model.
METHODS: Forty-five male white Wistar rats were randomized into three experimental groups (n=15): Normal control group (NC), silicon group (SIL), PRP treated group (SIL/PRP). In NC group left sciatic nerve was exposed through a gluteal muscle incision and after homeostasis muscle was sutured. In SIL group left sciatic nerve was exposed the same way and transected proximal to tibio-peroneal bifurcation leaving a 10-mm gap. Proximal and distal stumps were each inserted into a silicone conduit and filled with 10 µL phosphate buffered solution. In SIL/PRP group silicon conduit was filled with 20 µL PRP. Each group was subdivided into three subgroups of five animals each and were studied 4, 8, 12 weeks after surgery.
RESULTS: The animals were comparable regarding the baseline characteristics. Behavioral testing, sciatic nerve functional study and gastrocnemius muscle mass showed earlier regeneration of axons in SIL/PRP than in SIL group.
CONCLUSIONS: Local administration of PRP combined with silicon grafting could accelerate functional recovery of peripheral nerve.  Easily available growth factors and bioactive proteins present in PRP may have clinical implications for the surgical management of patients after nerve transection.

This study aimed at evaluating the effects of red and blue light-emitting diodes (LED) and low-level laser (LLL) on the regeneration of the transected sciatic nerve after an end-to-end neurorrhaphy in rabbits. Forty healthy mature male New Zealand rabbits were randomly assigned into four experimental groups: control, LLL (680 nm), red LED (650 nm), and blue LED (450 nm). All animals underwent the right sciatic nerve neurotmesis injury under general anesthesia and end-to-end anastomosis. The phototherapy was initiated on the first postoperative day and lasted for 14 consecutive days at the same time of the day. On the 30th day post-surgery, the animals whose sciatic nerves were harvested for histopathological analysis were euthanized. The nerves were analyzed and quantified the following findings: Schwann cells, large myelinic axons, and neurons. In the LLL group, as compared to other groups, an increase in the number of all analyzed aspects was observed with significance level (P < 0.05). This finding suggests that postoperative LLL irradiation was able to accelerate and potentialize the peripheral nerve regeneration process in rabbits within 14 days of irradiation.

The objective was to assess the effect of locally administered curcumin on peripheral nerve regeneration and functional recovery. Thirty male healthy white Wistar rats were divided into two experimental groups (n = 15), randomly: In control group (CG), the left sciatic nerve was exposed and transected proximal to tibio-peroneal bifurcation leaving a 10-mm gap. Proximal and distal stumps were each inserted into a silicone tube and filled with 10 μL sterilized olive oil. In treatment group (TG), the graft was filled with 10 μL curcumin (5 mg/mL) solved in olive oil. Each group was subdivided into three subgroups of five animals each and regenerated nerve fibers were studied 4, 8 and 12 weeks after surgery. Behavioral testing, sciatic nerve functional study, static sciatic index (SSI), gastrocnemius muscle mass and morphometric indices confirmed faster recovery of regenerated axons in TG than CG group (p < 0.05). In immunohistochemistry, location of reactions to S-100 in TG was clearly more positive than that in CG group. When loaded in a silicone tube, curcumin improved functional recovery and morphometric indices of sciatic nerve. Curcumin is readily available and its local application is easily performed without limitations of its poor bioavailability in systemic administration.