Tendon allograft sterilized by peracetic acid/ethanol combined with gamma irradiation.

BACKGROUND: Research and clinical applications have demonstrated that the effects of tendon allografts are comparable to those of autografts when reconstructing injured tendons or ligaments, but allograft safety remains problematic. Sterilisation could eliminate or decrease the possibility of disease transmission, but current methods seldom achieve satisfactory sterilisation without affecting the mechanical properties of the tendon. HYPOTHESIS: Peracetic acid-ethanol in combination with low-dose gamma irradiation (PE-R) would inactivate potential deleterious microorganisms without affecting mechanical and biocompatible properties of tendon allograft. STUDY DESIGN: Controlled laboratory design. METHODS: HIV, PPV, PRV and BVDV inactivation was evaluated. After verifying viral inactivation, the treated tendon allografts were characterised by optical microscopy, scanning electron microscopy and tensile testing, and the cytocompatibility was assessed with an MTT assay and by subcutaneous implantation. RESULTS: Effective and efficient inactivation of HIV, PPV, PRV and BVDV was observed. Histological structure and ultrastructure were unchanged in the treated tendon allograft, which also exhibited comparable biomechanical properties and good biocompatibility. CONCLUSION: The preliminary results confirmed our hypothesis and demonstrated that the PE-R tendon allograft has significant potential as an alternative to ligament/tendon reconstruction. CLINICAL RELEVANCE: Tendon allografts have been extensively used in ligament reconstruction and tendon repair. However, current sterilisation methods have various shortcomings, so PE-R has been proposed. This study suggests that PE-R tendon allograft has great potential as an alternative for ligament/tendon reconstruction. WHAT IS KNOWN ABOUT THIS SUBJECT: Sterilisation has been a great concern for tendon allografts. However, most sterilisation methods cannot inactivate viruses and bacteria without impairing the mechanical properties of the tendon allograft. WHAT THIS STUDY ADDS TO EXISTING KNOWLEDGE: Peracetic acid/ethanol with gamma irradiation can effectively inactivate viruses and bacteria. Meanwhile, tendon allografts sterilised by this method maintain their physiological tendon structure, biomechanical integrity and good compatibility.

Quantitative Proteomics Analysis of Differentially Expressed Proteins in Serum of Former Uranium Miners by Isobaric Tags for the Relative and Absolute Quantitation.

The carcinogenicity of radon has been convincingly documented through epidemiological studies of underground miners. However, there is a lack of early warning indicators for radon radiation damage. In this study, mixed serum samples of 3 groups were collected from 27 underground uranium miners and seven aboveground miners according to the radiation exposure dose. The differentially expressed proteins in the serum were identified using the isobaric tags for the relative and absolute quantitation (iTRAQ)-based method. Some differentially expressed proteins were validated by enzyme-linked immunosorbent assay (ELISA) in 84 underground and 32 aboveground miners. A total of 25 co-differentially expressed proteins in 2 underground miner groups were screened, of which 9 were downregulated and 13 were upregulated. Biological process analysis of these proteins using Metascape showed that 5 GO terms were enriched, such as negative regulation of very-low-density lipoprotein particle clearance, endocytosis, and regulated exocytosis. The results of the ELISA for the expression levels of GCN1, CIP2A, and IGHV1-24 in the serum of 116 miners' serum showed that the levels of GCN1 and CIP2A were consistent with the iTRAQ results. In conclusion, APOC1, APOC2, APOC3, ORM1, ORM2, ANTXR1, GCN1, and CIP2A may be potential early markers of radon radiation damage.

MicroRNA profiling in BEAS-2B cells exposed to alpha radiation reveals potential biomarkers for malignant cellular transformation.

The carcinogenicity of radon has been convincingly documented through epidemiological studies of underground miners. The risk of lung cancer from radon exposure is due to the continuous radioactive decay of this gas and subsequent emission of high-energy alpha decay particles. And the bronchial epithelial cells are the main targets of radon exposure. However, there is a lack of early warning indicators of lung cancer caused by radon in the physical examination of populations involved in occupations with higher exposure to radon. To assess the potential of a molecular-based marker approach for the early detection of human lung cancer induced by radon, human bronchial epithelial cell injury models induced by alpha-particle irradiation were constructed. The results of transwell migration assay, transwell invasion assay, and the expression of the epithelial-mesenchymal transition-related proteins showed that malignant cell transformation could be triggered by alpha irradiation. Potential microRNAs (miRNAs) (hsa-miR-3907, hsa-miR-6732-3p, hsa-miR-4788, hsa-miR-5001-5p, and hsa-miR-4257) were screened using miRNA chips in cell models. The pathway analyses of miRNAs selected using DIANA-miRPath v3.0 showed that miRNAs involved in malignant cell transformation were associated with cell adhesion molecules, extracellular matrix receptor interaction, and proteoglycans in cancer, among others, which are closely related to the occurrence and development of carcinogenesis. Reverse Transcription Quantitative Real-Time PCR (RT-qPCR) assay showed that five screened miRNAs were up-regulated in five lung cancer tissue samples. In conclusion, the results indicated that hsa-miR-3907, hsa-miR-6732-3p, hsa-miR-4788, hsa-miR-5001-5p, and hsa-miR-4257 may be potential early markers of the malignant transformation of bronchial epithelial cells induced by alpha-particle irradiation.

Radiation Exposure-Induced Changes in the Immune Cells and Immune Factors of Mice With or Without Primary Lung Tumor.

Recent studies have demonstrated that radiation activates in situ antitumor immunity and consequently induced a synergistic effect of radiotherapy and immunotherapy. However, studies related to radiation-induced changes in immune system of tumor-bearing mice are limited, which are of great significance to improve the efficacy of radioimmunotherapy. In this study, we first established a primary lung tumor mouse model using urethane. Then part of the right lung of the mouse was exposed to X-ray irradiation with a computed tomography-guided small animal irradiator and the changes of immune cells in both peripheral blood and spleen were determined by flow cytometry. Besides, the levels of both cytokines and immunoglobulins in mouse serum were detected by a protein chip. We found that B lymphocytes increased while CD8+ T lymphocytes reduced significantly. Interleukin-3 (IL-3), IL-6, regulated upon activation, normally T-expressed, and presumably secreted factor (RANTES), and vascular endothelial growth factor (VEGF) were found to be decreased after tumor formation, and the similar results have also been observed with kappa, IgG3, IgE, IgM, and IgG2a. After irradiation, lower concentrations of IgD, kappa, and IgM were found in the serum. Our findings indicate that localized tumor irradiation caused some obvious changes like inhibiting the ability of innate immunity, and these changes may be useful in predicting prognosis.

[A review of studies on hair follicle dermal sheath cells].

The dermal sheath surrounding the outside of the hair follicle maintains and regenerates the dermal papilla, a necessary component for hair regeneration. Dermal sheath cells participate in skin wound healing and have some characteristics of adult stem cells such as immuneprivilege, multiple differentiation and plasticity. It is likely that dermal sheath cells will be the new cynosure in the research on wound healing and tissue engineering. Here we review the studies of hair follicle dermal sheath in present years.

Synthesis and characterization of amphiphilic photocleavable polymers based on dextran and substituted-ɛ-caprolactone.

In this study, we synthesized photocleavable amphiphilic block copolymers containing photodegradable linkers, 5-hydroxy-2-nitrobenzyl alcohol, as junction points between hydrophilic dextran (or maltodextrin) and hydrophobic poly(4-substituted-ɛ-caprolactone) chains, by using a combination of ring-opening polymerization and nucleophilic substitution reactions. When the polymer solutions were exposed to ultraviolet (UV) irradiation, major structural and morphological changes were observed in the particles. The copolymers were biodegradable and biocompatible, and they can self-assemble into spherical photoresponsive micelles. Fluorescence emission measurements indicated the release of Nile red, a hydrophobic dye, encapsulated by the Dex-ONB-PXCL micelles, in response to irradiation caused by the disruption of the micelles. Light-triggered bursts were observed for indomethacin (IMC)-loaded Dex-ONB-PXCL micelles during the first 5 h. The nanoparticles were associated with nonsignificant toxicity at concentrations of less than 100 µg mL(-1). The confocal microscopy and flow cytometry results showed that the uptake of DOX-loaded micelles by HeLa cells was slightly less than that of free DOX, and it was predominantly retained in the cytoplasm.

[Porcine acellular dermal matrix for repair of abdominal wall defects in rabbit model].

OBJECTIVE: To research the effect of porcine acellular dermal matrix in the reconstruction of abdominal wall defects in rabbits, and to investigate the application feasibility of xeno-transplantation of acellular dermal matrix. METHODS: The porcine acellular dermal matrix was prepared from a health white pig. Twenty-six Japanese white rabbits (weighing 2.2-2.3 kg, female or male) were randomly assigned to 2 groups: the control group (n=6) and the experimental group (n=20). In the control group, the full-thickness abdominal wall defect of 5.0 cm x 0.5 cm was made, and the defect was sutured directly; in the experimental group, the full-thickness abdominal wall defect of 5.0 cm x 2.5 cm was made, and the defect was repaired with porcine acellular dermal matrix patch at the same size as the defect. At 5 weeks after surgery, the incidence of hernia and the intra-abdominal adhesions were observed and the wound breaking strength was compared between the patch-fascia interface and the fascia-fascia interface. The graft vascularization was evaluated through histological analysis at 6 months after surgery in the experimental group. RESULTS: No hernia occurred in all rabbits of 2 groups. At 5 weeks after surgery, healing was observed between patch and the muscular fascia; the vascularization was seen in the porcine acellular dermal matrix patch. There was no significant difference in the adhesion grade (Z= -0.798, P=0.425) between the experimental group (grade 2 in 1 rabbit, grade 1 in 5, and grade 0 in 12) and the control group (grade 1 in 1 and grade 0 in 5). No significant difference was found (t= -0.410, P=0.683) in the breaking strength between the patch-fascia interface in the experimental group [(13.0 +/- 5.5) N] and the fascia-fascia interface in control group [(13.6 +/- 4.0) N]. In the experimental group, the small vessels and the infiltration of inflammatory cells were observed in the porcine acellular dermal matrix patch after 5 weeks through histological observations. The junctions of the patch-fascia interface healed with fibrous connective tissue. At 6 months after surgery, the inflammation was subsided and the collagen fiber of the patch was reconstructed. CONCLUSION: The porcine acellular dermal matrix patch has good results in repairing full-thickness abdominal wall defect. The patch-fascia interface has similar breaking strength to the fascia-fascia interface. The collagen fibers of the patch are reconstructed.

[Study on cytotoxicity of microdoses peracetic acid in vitro].

OBJECTIVE: To evaluate the cytotoxicity of microdoses peracetic acid (PAA) so as to provide the evidence for making residual limit of PAA sterilization. METHODS: Mouse fibroblasts (L929 cell line) cultured in vitro were observed to evaluate the influence of microdoses PAA including 1 x 10(-6), 2 x 10(-6), 3 x 10(-6), 4 x 10(-6), 5 x 10(-6), and 10 x 10(-6) (V/V). The proliferation of cells was determined by MTT assay at 2, 4, and 7 days of culture. The growth curve and the relative growth rate (RGR) were obtained. The cytotoxicity of PAA at different concentrations was evaluated according to RGR. RESULTS: At 2, 4, and 7 days after culture, fibroblasts of 1 x 10(-6) group grew with normal morphology analogous to control group, while the cell growth of other groups were poor. With the increase of PAA concentration, the absorbance (A) values decreased, which suggested that there was a significant negative correlation between cell proliferation and PAA concentration. And the correlation coefficient was -1.000 at 2 and 4 days, - 0.964 at 7 days. There was no significant difference in A value between 1 x 10(-6) group and the control group (P > 0.05), while there were significant differences in A value between the control group and other concentration groups (P < 0.05). The growth curve of 1 x 10(-6) group was similar to that of the control group, both had obvious phase of exponential growth. The growth curves of other groups had no obvious phase of exponential growth. The cytotoxicity of 1 x 10(-6) group was classified as level 1, 2 x 10(-6) group as level 2, 3 x 10(-6) group as level 3, 4 x 10(-6) group as level 3-4, 5 x 10(-6) group and 10 x 10(-6) group as level 4. CONCLUSION: PAA of 1 x 10(-6) had no obvious cytotoxicity. The residual limit of PAA less than 1 x 10(-6) was recommended.

[Experimental study on porcine acellular dermal matrix and split-thickness skin grafts to repair full-thickness skin defects].

OBJECTIVE: To compare the effect of the composite skin graft consisting of split-thickness skin grafts (STSGs) and porcine acellular dermal matrix (PADM) with STSGs only, and to histologically observe the turnover of the PADM in rats. METHODS: Twenty female Sprague-Dawley rats, weighing 200-225 g, were included. The size of 4.0 cm x 2.5 cm PADM was implanted into hypoderm of the left side of Sprague-Dawley rats' back. After 10-14 days, the size of 4.0 cm x 2.5 cm full-thickness skin defects were made on the left to expose the PADM under the skin and the same size of full-thickness skin defects were made on the right of the rats' back. The excised full-thickness skin was made to STSGs about 0.2 mm by drum dermatome. The defects were grafted with composite skin (STSGs on the PADM, experimental group) and STSGs only (control group). The survival rate, the construction degree of grafts, and the histological change in grafts area were observed at 2, 4, 8, and 20 weeks after operation. RESULTS: At 2 weeks after STSGs (0.2 mm) placed on vascularized PADM, STSGs and PADM adhered together and the composite skin had a good survival. The control group also had a good survival. Histological observations showed that STSGs and PADM grew together, neutrophilic granulocytes and lymphocytes infiltrated in the PADM and some macrophages around the PADM. Fibrous connective tissues were filled under the STSGs in control group. At 4-8 weeks after transplantation, the composite skin had a good survival and the composite skin was thick, soft, and elastic. STSGs survived almost totally in control group, but the grafts were thin. Histological observations showed that inflammatory reactions of PADM faded gradually in experimental group; scar tissues formed under the STSGs in control group. At 20 weeks after transplantation, composite skin was flat, thick, and elastic in experimental group, but the STSGs were thinner and less elastic in control group. Histological observations showed that histological structures of the PADM were similar to the dermal matrix of rats, and the results showed that the collagen matrix of PADM was gradually replaced by the rats' collagen matrix. Scar tissues were filled under the STSGs in control group. Wound healing rates of experimental group were lower than those of control group at 4 and 8 weeks (P < 0.05); wound contraction rates of experimental group had lower tendency than those of control group, but showing no significant differences (P > 0.05). CONCLUSION: Coverage wound with composite skin which composed of STSGs and PADM could improve wound healing quality; the composite skin is thicker and better elastic than STSGs only. The collagen matrix of PADM is gradually replaced by rats' collagen matrix.