Objective: Inducing human amniotic membrane mesenchymal stem cells (hAMSCs) to Schwann cells-like cells (SCs-like cells) in vitro, and to evaluate the efficacy of transplantation of hAMSCs and SCs-like cells on nerves regeneration of the rat flaps.

Objective: To explore the effects of combined transplantation of the rat Schwann cells and fibroblasts (Fbs) on the nerve regeneration of denervated perforator flaps in rats and the mechanism. Methods: (1) Fbs were isolated from the trunk of 2 Sprague-Dawley (SD) rats embryos of 14-16 days′ pregnancy and cultured, and the morphology of the cells was observed. The third passage of cells were used for subsequent experiments. The protein expressions of fibronectin and Ephrin-B2 were observed by immunohistochemical method. The mRNA expression of Ephrin-B2 was detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction (n=3). (2) Schwann cells were isolated from the bilateral sciatic nerves and brachial plexus nerves of 45 SD rats born for 1-3 days and cultured, and the morphology of the cells was observed. The third passage of cells were used for subsequent experiments. The rate of S100 positive cells was detected by immunofluorescence method and flow cytometer, with sample numbers of 9 and 3 respectively. (3) In Dulbecco′s modified Eagle medium (DMEM) high glucose medium, 1 mL Fbs and 1 mL Schwann cells both in the concentration of 1×10⁵ cells/mL were co-cultured as Schwann cells+ Fbs co-culture group, and 2 mL Schwann cells in the concentration of 1×10⁵ cells/mL were cultured alone as Schwann cells alone culture group, with 5 wells in each group. The clusters of Schwann cells in the two groups were observed and counted under inverted phase contrast microscope at post culture hour (PCH) 6 and 24 respectively. The clusters of Schwann cells in Schwann cells+ Fbs co-culture group were observed by immunofluorescence method at PCH 24 too. The protein expressions of EphB2, Sox2, and N-cadherin in Schwann cells of two groups at PCH 24 were detected by Western blotting (n=20). (4) Totally 100 8-week-old male SD rats were selected, and an in situ replanted peritoneal denervated perforator flap was made in each rat. According to the random number table, the rats were divided into simple flap group, Fbs alone transplantation group, Schwann cells alone transplantation group, Schwann cells+ Fbs co-transplantation group, with 25 rats in each group. Flaps of rats in Fbs alone transplantation group and Schwann cells alone transplantation group were injected with 0.4 mL Fb and 0.4 mL Schwann cells respectively (2×10⁶ cells each). Flaps of rats in Schwann cells+ Fbs co-transplantation group were injected with 0.4 mL Fbs and Schwann cells mixed cells (totally 2×10⁶ cells, cell number ratio: 1∶1), and flaps of rats of simple flap group were injected with the same volume of DMEM high glucose medium. On post injection day (PID) 2, 5, 7, 9, and 14, 5 rats in each group were selected respectively according to the random number table. The flap tissue was collected, and the number, diameter, and arrangement of regenerated nerves were observed by immunofluorescence method. Data were processed with completely random designed t test, analysis of variance for repeated measurement, t test, and Bonferroni correction. Results: (1) The third passage of cells isolated and cultured from the rat embryo trunks were uniform in size and shape, long spindle-shaped, with a large proportion of nuclei. Strong positive expressions of fibronectin and Ephrin-B2 protein in cells were observed, and the mRNA expression of Ephrin-B2 was 0.004 1±0.000 8. The cells were identified as Fbs. (2) After 5 days of culture, the primary cells isolated from the sciatic nerves and brachial plexus nerves of neonatal rats were elongated in cell bodies and grew in nest, fence, or vortex-like shape. The third passage of cells were detected by immunofluorescence method and flow cytometer, and the corresponding S100 positive cell rates were (95.9±1.0)% and (95.8±1.1)% respectively. The cells were identified as Schwann cells. (3) At PCH 6 and 24, the cluster numbers of Schwann cells in Schwann cells+ Fbs co-culture group were significantly higher than those of Schwann cells alone culture group (t=6.500, 10.614, P<0.01). At PCH 24, the Schwann cells in Schwann cells+ Fbs co-culture group aggregated into clusters, Fbs dispersed around the Schwann cell clusters, and the protein expressions of EphB2, N-cadherin, and Sox2 in Schwann cells were significantly higher than those in Schwann cells alone culture group (t=2.975, 19.717, 11.159, P<0.05 or P<0.01). (4) On PID 2, a small number of scattered, disordered, short, and thin nerve fibers were observed in the flap tissue of rats in the four groups. From PID 5 to 14, the number of nerve fibers in the flap tissue of rats of Schwann cells+ Fbs co-transplantation group increased gradually, and the nerve fibers were with long diameter and arranged orderly. The number of nerve fibers in the flap tissue of rats of Schwann cells alone transplantation group increased, but the nerve fibers were with short diameter and arranged disorderly, and the number was smaller than that of Schwann cells+ Fbs co-transplantation group. In simple flap group and Fbs alone transplantation group, the nerve fibers in the flap tissue of rats gradually degenerated with gradually decreased number or even disappeared. Conclusions The combined transplantation of Fbs and Schwann cells in rats can regulate Schwann cells migration and clustering by activating Ephrin/Eph-Sox2-N-cadherin signaling pathway, thus promoting the orderly nerve regeneration of denervated perforator flaps in rats.

Objective: To investigate the effects of free mini-flap on tibial side of third toe on repairing skin and soft tissue defect of finger pulp at the end of finger. Methods: From August 2013 to May 2017, 18 patients with skin and soft tissue defect of finger pulp at the end of finger were admitted to our unit, with 12 men and 6 women aged 16 to 54 years. As the skin and soft tissue defect sites, there were 3 cases of thumb, 8 cases of index finger, 4 cases of middle finger, and 3 cases of ring finger. The area of defects ranged from 2.0 cm×1.4 cm to 3.5 cm×2.4 cm. Free mini-flaps on tibial side of third toes were designed according to area and shape of defects, and the length and width of flaps were 0.1 to 0.2 cm longer than the length and width of the defects, respectively. The area of flaps ranged from 2.1 cm×1.5 cm to 3.7 cm×2.6 cm. The end-to-end anastomosis of subcutaneous veins of flaps and superficial veins of the finger-palm side or superficial dorsal digital vein, the end-to-end tension-free anastomosis of the base metatarsal arteries on tibial side of third toe and proper digital arteries of recipient finger were performed. Besides, anastomosis of base metatarsal nerve on tibial side of third toe and proper digital nerve of recipient finger was performed. The donor sites on feet were sutured directly or repaired with full-thickness skin grafts on medial upper leg of the same side. The survival of flaps after operation and the follow-up of patients were observed. Results: All flaps survived well, with good blood supply. Among the 18 patients, 2 patients lost to follow-up, and 16 patients were followed up for 4 to 36 months. The shape and texture of flaps were good. After reconstruction, finger pulps at the end of finger were plump, with fingerprint. Function of the finger restored well, and the two-point discriminatory distances of flaps were 5 to 10 mm. The donor sites on feet of 14 patients healed after the operation, the other 2 patients had necrosis on edge and central area of skin grafts, and the necrotic area healed after dressing change. The skin graft areas on feet were wear-resistant, with slight damage to donor sites and did not influence shoes wearing and walking. Besides, patients did not feel uncomfortable. Conclusions Skin and soft tissue defects of finger pulp at the end of finger repaired by free mini-flaps on tibial side of third toe are with good shape and slight damage to donor sites, and the operation is simple. It is worthy of popularization and application in clinic.

Objective: To explore the effect of the perforator flap of the proper digital artery on the ulnar or radial side of the finger in the treatment of webbed scar contracture of the same finger in child. Methods: From January 2012 to January 2016, 26 children who were treated with dressing change after burn of finger and then had webbed scar contracture along with growth and development were hospitalized in our unit, involving a total of 50 fingers. There were 14 males and 12 females among the children aged from 2 to 14 years. After the scar was dissected and released, the wound area ranged from 1.6 cm×1.0 cm to 5.0 cm×2.6 cm. The perforator flap of the proper digital artery of the ulnar or radial side of the same finger was used to repair the wound. The flap area ranged from 1.8 cm×1.0 cm to 4.6 cm×1.8 cm. The donor sites were sutured directly. The residual wounds in donor and recipient sites were repaired by full-thickness skin graft collected from inguinal area/adjacent area or adjacent perforator flap. The postoperative development and function of the fingers were followed up and observed. The range of motion of the fingers was evaluated according to the Chinese Medical Association Hand Surgery Society′s upper limb functional evaluation trial standard, the Kantor Scar Cosmesis Assessment and Rating Scale was used to score the scar of finger, and the latest data were recorded. Results: The flaps and skin grafts survived successfully after operation. The patients were followed up for 6 to 24 months. The perforator flaps of the proper digital artery on the ulnar or radial side of the finger survived well at the latest follow-up, with good color and texture and a two-point discrimination distance of 9 to 12 mm. There was no contracture of the fingers, a little pigmentation in the skin graft area, no flexion deformity of the fingers, no lateral bending of the fingers to the flap-harvesting side, and no scar contracture at the webs of the fingers. Compared with that of healthy side, the development of finger was not obviously abnormal. The range of motion of the fingers was excellent in 38 fingers and good in 12 fingers, and the scar score of the fingers was 2-3 points in 31 fingers, 4-7 points in 15 fingers, and 8-10 points in 4 fingers. Conclusions The efficacy of perforator flap of the proper digital artery of the ulnar or radial side of finger in the treatment of the webbed scar contracture of the same finger in child is reliable, with high postoperative survival rate of the flap, better color and texture, and fewer complications, which can avoid the risk of re-contracture of the finger in a short period after operation, and does not affect the growth and development of the finger.