OBJECTIVETo investigate the immunological characteristics of human tonsil mesenchymal stem cells (TMSCs).

METHODSHuman tonsil tissues were obtained from the children patients with chronic tonsillitis. TMSCs were separated, cultured, and were detected the expression profiles of HLA-I, HLA-II, CD80, CD86 by flow cytometry. The measurement of immunogenicity, the effect on phytohemagglutinin (PHA) induced peripheral blood mononuclear cell (PBMCs) proliferation and mixed lymphocytes reaction (MLR) were performed to identify the immunological characteristics of TMSCs. The co-cultures of TMSCs + PBMCs + PHA and TMSCs + MLR were established, respectively, and the concentration of kynurenine, which is the metabolin of indoleamine 2, 3-dioxygenase, in the culture supernatant were examined. Then we added 1-methyl-L-tryptophan into the co-culture of TMSCs + PBMCs + PHA and TMSCs + MLR, respectively, and tested the proliferation of PBMCs. Each experiment was repeated three times, and there were six samples in each group. Statistical significance was assessed by analysis of variance (ANOVA), and a P value less than 0.05 was considered statistically significant.

RESULTSTMSCs expressed HLA-I, were negative for HLA-II and co-stimulatory molecules CD80 and CD86. The stimulation index in the group of TMSCs + allogeneic PBMCs was 1.38 ± 0.26, whereas the stimulation index in the group of allogeneic PBMCs was 1.22 ± 0.28, and there was no significant difference between the two groups (P > 0.05), indicating that TMSCs could not initiate the proliferation of allogeneic PBMCs. The stimulation indexes in the group of TMSCs + allogeneic PBMCs + PHA were 1.49 ± 0.29 and 1.23 ± 0.22, respectively, whereas the stimulation index in the group of allogeneic PBMCs + PHA was 4.60 ± 0.81, and the difference between the two groups had a statistical significance (P < 0.05) suggesting that TMSCs could inhibit PHA-induced PBMCs proliferation. The stimulation indexes in the group of TMSCs + MLR were 1.29 ± 0.23 and 1.26 ± 0.27, respectively, however, the stimulation index in the group of MLR was 3.04 ± 0.66, and the difference between the two groups had a statistical significance (P < 0.05), demonstrating that TMSCs could suppress MLR-induced PBMCs proliferation. The levels of kynurenine were (26.0 ± 2.3) μmol/L and (23.5 ± 4.5) μmol/L in the culture of TMSCs + PBMCs + PHA and TMSCs + MLR, respectively, thus elevating significantly. After adding of 1-methyl-L-tryptophan, TMSCs-mediated-proliferation suppression of PBMCs restored to normal levels.

CONCLUSIONTMSCs possess low immunogenecity and immunosuppressive function, may be used in allogeneic transplantation.

Cell Proliferation ; Cells, Cultured ; Child ; Coculture Techniques ; Flow Cytometry ; Humans ; Immunosuppression ; Kynurenine ; analysis ; Leukocytes, Mononuclear ; Lymphocyte Culture Test, Mixed ; methods ; Mesenchymal Stromal Cells ; cytology ; immunology ; Palatine Tonsil ; cytology ; Tryptophan ; administration & dosage ; analogs & derivatives

Objective To explore the surgical technique and clinical effect of percutaneous lumbar endoscopic surgery for central disc herniation.Methods From February 2010 to April 2014,69 consecutive patients (36 males and 33 females) with central lumbar disc herniation underwent percutaneous endoscopic surgery were included in the study.The average age was 31.33±8.27 years,ranging from 16 to 56 years.All operations were performed by increasing the initial puncture angle.First enter the intervertebral space through the ventral nerve root,and then move the guide rod tip step by step to the top of the protrusion.Operative time,intraoperative blood loss and complications were recorded.Visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) and Oswestry disability index (ODI) were followed up before surgery,immediately after surgery,3,12,24 months after surgery.The MacNab criteria were used to evaluate the efficacy at the last follow-up.During the follow-up period,X-ray,CT and MRI were performed to observe the instability and recurrence of the operative segment.Results All of the disc herniations were successfully removed without conversion to open surgery or revision.All patients were followed up for more than 24 months.The VAS scores of low back pain and leg pain were significantly lower than those before operation immediately,3 months,12 months and 24 months after operation (P＜0.01).The JOA score was significantly higher in monthly follow-up (P＜0.01),and ODI was significantly improved in 3 months and 24 months after operation (P＜ 0.01).There were 22 excellent cases (31.88％),44 good cases (63.77％),3 cases (4.35％) during the final follow-up,and the excellent and good rate was 95.65％.Dural sac injuries occurred in 1 patient and discharged from hospital in 2 weeks of symptomatic treatment.Lumbar instability and operative segment recurrence were not found during the follow-up period (2 years).Conclusion The improvement of the puncture angle and the technique innovation of the guide rod moving from intervertebral space to intraspinal canal step by step can effectively reduce the nerve root stimulation and injury during the puncture and the placement of the working passage,and significantly improve the clinical efficacy of percutaneous lumbar endoscopy in the treatment of central lumbar disc herniation.Microscopic management of the posterior longitudinal ligament can effectively reduce the recurrence rate and has no significant impact on spinal stability.