BACKGROUND:Sirius red is a strong acid anionic dye. Being not-easyto-fade and specific, sirius red becomes the best dye for collagen staining.Collagen is a major component of extracellular matrix and has some specific physiological functions. Through synthesis and reconstruction of collagen, bone fracture repair will be accomplished.OBJECTIVE: Picric acid-Sirius red stained slides were observed under a polarized light microscopy for evaluation the dynamic changes in the ratio of different collagen types and their distributions in bone fracture healing.DESIGN: It was a controlled observation.SETTING: It was conducted in the Department of Orthopedics, Renmin Hospital, Wuhan University; Department of Traumatic Orthopaedics, Tianjin Hospital; Department of Traumatic Orthopaedics, Jishuitan Hospital,Medical Department, Peking University; Tissue Engineering Center of Institute of Basic Medical Sciences, Academy of Military Medical Sciences of Chinese PLAMATERIALS: It was conducted at Tissue Engineering Center of Institute of Basic Medical Sciences, Academy of Military Medical Sciences of Chinese PLA from March 2002 to September 2003. Three healthy adult Chinese sheep, male and in weight from 25 to 35 g, were selected.METHODS: All the animals were anesthesized and sterilized; a transverse osteotomy of the trunk of metatarsus was performed; and the end of fracture was fixed with a six-hole Medoff sliding plate. At the post-operative month 1, 3 and 6, samples were taken from bone fractures. After decalcification with EDTA, they were stained with Picric acid-sirius red, and the types and distribution of collagens were observed under a polarized light microscopy.MAIN OUTCOME MEASURES: Types and distributions of collagens in bone lesion in different period of bone healing were investigated.RESULTS: Three sheep used in this study entered the statistical analysis.①Morphological features of various collagens under a polarized light microscopy postoperatively: Type Ⅰ collagen packed tightly, with a strong refraction and yellow, orange or red thick fibres. Type Ⅱ collagen formed a loose reticulation with fibres exhibiting different colour and a weak refraction. Thin fibres of type Ⅲ collagen with weak refraction and green colour formed a loose reticulation. ②Quantitative studies on various collagens under a polarized light microscopy postoperatively: At postoperative month 1,red or orange fibres (type Ⅰ collagen) were rarely seen in bone fracture,while green fibres (typical of type Ⅲ collagen) were dominant with a disorder pack. At postoperative month 3, red or orange fibres increased significantly and the ratio of type Ⅲ collagen reduced. The collagen fibres assembled regularly. At postoperative month 6, thick yellow-red collagen became dominant and thin green type Ⅲ collagen decreased dramatically and arranged in an obvious oblique, spiral and crossed orientations.CONCLUSION: Picric acid-sirius red stain combined with polarized light microscopy technique is not only capable of identifing type Ⅰ and type Ⅲ collagens in bone fraction, but also can reflect the morphological features,distribution and the ratio of these two type collagens. This approach has the virtues of easiness in operation, strong specificity and high sensitivity.

In order to study the chondrogenic phenotype differentiation of adult sheep bone marrow-derived mesenchymal stem cells (MSCs) in a defined medium as potential seed cells for cartilage tissue engineering. MSCs were isolated by density centrifugation with Percoll solution from bone marrow aspirated from sheep iliac crest. The third passage of MSCs were induced with H-DMEM containing TGF-beta3, IGF-I, Dexamethasone and VitC. The shape and ultrastructure of cells were observed, toluidine blue stain for GAG and immunohistochemistry for type II collagen were applied for chondrogenic phenotype identification. After 14 days of induction, MSCs changed from a spindle-like appearance to a polynal shape, a large amount of endoplasmic reticulum, Golgi complex and mitochondria were observed, and the differentiation of MSCs chondrogenic phenotype was verified by positive staining of toluidine blue and immunohistochemistry. MSCs derived from bone marrow can differentiate to chondrogenic phenotype when induced in vitro and can be used as optimal seed cells for cartilage tissue engineering.
Bone Marrow Cells/*cytology ; Cell Differentiation ; Cell Separation ; Cells, Cultured ; Chondrocytes/*cytology ; *Chondrogenesis ; Mesenchymal Stem Cells/*cytology ; Phenotype ; Sheep ; Tissue Engineering

BACKGROUND: Polymorphism in promoter region can change the expression of genes, which may be associated with susceptivity of diseases. Gene polymorphism of interleukin-6 (IL-6) promoter is associated with nationality and many diseases. Different nationalities often display different characteristics of gene polymorphism.OBJECTIVE: To observe the distribution of polymorphism at sites -597 and -572 in IL-6 promoter region in Tibet Tibetan population and to provide the theoretical data for Tibetan population genetics and background of immunity.DESIGN: Randomized investigation.SETTING: Institute of Anthropology, Jinzhou Medical College.PARTICIPANTS: Totally 108 healthy Tibetan teenagers were selected from Lasa and Naqu region in Tibet autonomous region from October 2003 to July 2004, including 60 males and 48 females, aged from 14-21 years. Inclusive criteria:The parents of the volunteers were healthy Tibetans after body examination. The volunteers knew the fact, agreed to participate into the trail and signed the informed consent.METHODS: 5 mL peripheral vein blood was collected from 108 Tibetan teenagers. DNA from human leucocytes was extracted by salt fractionation. IL-6 promoter including -597 and -572 fragments was amplified by polymerase chain reaction (PCR). Representative fragments were cloned then sequenced after restriction fragment length polymorphism (RFLP).MAIN OUTCOME MEASURES: Distribution of polymorphism in Tibet Tibetan population; Results after comparison with those of other nationalities including Han population.RESULTS: Data of 108 Tibetan teenagers were involved in the result analysis. ①Distribution of polymorphism on -572C/G site of IL-6 promoters in population of either sex: There were no GA and AA genotypes at site -597, but only GG genotype appeared. There were CC, CG and GG genotypes at site -572, and the frequencies were 0.63, 0.35 and 0.02 in order. Distribution of genotype with representativeness met the Hardy-Weinberg equilibrium. Allele frequencies were 0.81 and 0.19, respectively. There was no significant difference of either sex in genotype and allele frequency (P ＞ 0.05). ②Distribution of polymorphism on -597 G/A and -572 C/G in different nationalities: GG, GA, AA genotypes appeared on -597 site in England and France, and G and A allele frequencies were 0.60 and 0.40,respectively. It was significantly different from that of Tibetan in Tibet. Furthermore, Japanese had no polymorphism,which was similar to that of Hans in China (P ＞ 0.05). ③Genotype of different straps and results of DNA sequencing:Only GG genotype was found on -597 site (without the restriction site, one fragment after restriction, PCR amplification products), no GA and AA genotypes. CC, CG and GG genotypes appeared at site -572, and frequencies were 0.64,0.35 and 0.01, respectively. Distribution of genotype with representativeness met the Hardy-Weinberg equilibrium (P ＞0.05). Allele frequencies were 0.81 and 0.19, respectively. There was no significant difference of either sex in genotype and allele frequency. Distribution of gene frequency and allele frequency in IL-6 were similar between Tibetan and that of Hans, but it was significantly different from that of population in England, France and America.CONCLUSION: There are nationality differences of IL-6 gene polymorphism at sites -597 and -572. No polymorphism is found at site -597 in Tibetan. Race differences are seen at site -572, having CC, CG and GG genotypes and G allele is rate. Compared with white population, there is significant difference in genotype and allele frequency at site -572. Their characteristics are close to Hah population and Japanese, which may be associated with genetic gene of persons living in plateau.

Tissue-engineering bone with porous ,betatricalcium phosphate (3-TCP) ceramic and autologous bone marrow mesenchymal stem cells (MSC) was constructed and the effect of this composite on healing of segmental bone defects was investigated. 10-15 ml bone marrow aspirates were harvested from the iliac crest of sheep, and enriched for MSC by density gradient centrifugation over a Percoll cushion (1. 073 g/ml). After cultured and proliferated, tissue-engineering bones were constructed with these,cellS seeded onto porous f-TCP, and then the constructs were implanted in 8 sheep left metatarsus defect (25 mm in length) as experimental group. Porous ,-TCP only were implanted to bridge same size and position defects in 8 sheep as control group, and 25 mm segmental bone defects of left metatarsus were left empty in 4 sheep as blank group. Sheep were sacrificed on the 6th, 12th, and 24th week postoperatively and the implants samples were examined by radiograph, histology, and biomechanical test. The 4 sheep in blank group were sacrificed on the 24th week postoperatively. The results showed that new bone tissues were observed either radiographic or histologically at the defects of experimental group as early as 6th week postoperatively, but not in control group, and osteoid tissue, woven bone and lamellar bone occurred earlier than in control group in which the bone defects were repaired in "creep substitution" way, because of the new bone formed in direct manner without progression through a cartilaginous intermediate. At the 24th week, radiographs and biomechanical test revealed an almost complete repair of the defect of experimental group, only partly in control group. The bone defects in blank group were non-healing at the 24th week. It was concluded that engineering bones constructed with porous -TCP and autologous MSC were capable of repairing segmental bone defects in sheep metatarsus beyond "creep substitution" way and making it healed earlier. Porous ,-TCP being constituted with autologous MSC may be a good option in healing critical segmental bone defects in clinical practice and provide insight for future clinical repair of segmental defect.
Bone Marrow Cells/cytology ; Calcium Phosphates/*pharmacology ; Cells, Cultured ; Fractures, Bone/*therapy ; Implants, Experimental ; Mesenchymal Stem Cells/*cytology ; Metatarsus/*injuries ; Porosity ; Sheep ; Tissue Engineering

Tissue-engineering bone with porous β-tricalcium phosphate (β-TCP) ceramic and autologous bone marrow mesenchymal stem cells (MSC) was constructed and the effect of this composite on healing of segmental bone defects was investigated. 10-15 ml bone marrow aspirates were harvested from the iliac crestof sheep, and enriched for MSC by density gradient centrifugation over a Percoll cushion (1. 073 g/ml). After cultured and proliferated, tissue-engineering bones were constructed with these cells seeded onto porous β-TCP, and then the constructs were implanted in 8 sheep left metatarsus defect (25 mm in length) as experimental group. Porous β-TCP only were implanted to bridge same size and position defects in 8 sheep as control group, and 25 mm segmental bone defects of left metatarsus were left empty in 4 sheep as blank group. Sheep were sacrificed on the 6th, 12th, and 24th week postoperatively and the implants samples were examined by radiograph, histology, and biomechanical test. The 4 sheep in blank group were sacrificed on the 24th week postoperatively. The results showed that new bone tissues were observed either radiographic or histologically at the defects of experimental group as early as 6th week postoperatively, but not in control group, and osteoid tissue, woven bone and lamellar bone occurred earlier than in control group in which the bone defects were repaired in "creep substitution" way, because of the new bone formed in direct manner without progression through a cartilaginous intermediate. At the 24th week, radiographs and biomechanical test revealed an almost complete repair of the defect of experimental group, only partly in control group. The bone defects in blank group were non-healing at the 24th week. It was concluded that engineering bones constructed with porous β-TCP and autologous MSC were capable of repairing segmental bone defects in sheep metatarsus beyond "creep substitution" way and making it healed earlier. Porous β-TCP being constituted with autologous MSC may be a good option in healing critical segmental bonedefects in clinical practice and provide insight for future clinical repair of segmental defect.

In order to study the chondrogenic phenotype differentiation of adult sheep bone marrow-derived mesenchymal stem cells (MSCs) in a defined medium as potential seed cells for cartilage tissue engineering. MSCs were isolated by density centrifugation with Percoll solution from bone marrow aspirated from sheep iliac crest. The third passage of MSCs were induced with H-DMEM containing TGF-beta3, IGF-I, Dexamethasone and VitC. The shape and ultrastructure of cells were observed, toluidine blue stain for GAG and immunohistochemistry for type II collagen were applied for chondrogenic phenotype identification. After 14 days of induction, MSCs changed from a spindle-like appearance to a polynal shape, a large amount of endoplasmic reticulum, Golgi complex and mitochondria were observed, and the differentiation of MSCs chondrogenic phenotype was verified by positive staining of toluidine blue and immunohistochemistry. MSCs derived from bone marrow can differentiate to chondrogenic phenotype when induced in vitro and can be used as optimal seed cells for cartilage tissue engineering.
Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; Cell Separation ; Cells, Cultured ; Chondrocytes ; cytology ; Chondrogenesis ; Mesenchymal Stromal Cells ; cytology ; Phenotype ; Sheep ; Tissue Engineering

BACKGROUND:Sema3A is a power secretory osteoprotective factor.However,studies about Sema3A-modified dental pulp stem cells(Sema3A-DPSCs)are rare. OBJECTIVE:To explore the osteogenic differentiation ability of Sema3A-DPSCs and their regulatory effect on the osteogenic differentiation of the pre-osteoblast cell line MC3T3-E1. METHODS:First,Sema3A-DPSCs were constructed using a lentivirus infection system carrying the Sema3A gene.Control lentivirus-treated DPSCs(Vector-DPSCs)were used as controls.Sema3A-DPSCs or Vector-DPSCs were co-cultured with proosteoblast line MC3T3-E1 at the ratio of 1∶1 and 1∶3 for 24 hours.Finally,the Sema3A-DPSCs,Vector-DPSCs and their co-cultured cells with MC3T3-E1 were cultured for osteogenic induction and differentiation.Osteogenic gene expression was detected by alkaline phosphatase staining,alizarin red staining and real-time quantitative RT-PCR to evaluate osteogenic differentiation ability. RESULTS AND CONCLUSION:(1)Sema3A mRNA and protein expression levels in Sema3A-DPSCs were significantly up-regulated.The level of secreted Sema3A in cell supernatant was up-regulated.(2)Compared with the Vector-DPSCs,mRNA expressions of osteogenic genes alkaline phosphatase,Runt-related transcription factor 2,osteocalcin and Sp7 transcription factors in Sema3A-DPSCs were up-regulated;the activity of alkaline phosphatase was enhanced,and the formation of mineralized nodules increased.(3)There were no obvious differences in proliferation between Sema3A-DPSCs and Vector-DPSCs.(4)Compared with MC3T3-E1/Vector-DPSCs co-culture system,the expression of MC3T3-E1 osteogenic genes was up-regulated,and the total alkaline phosphatase activity was enhanced and more mineralized nodules were formed in the MC3T3-E1/Sema3A-DPSCs co-culture system.(5)The results suggest that overexpression of Sema3A can enhance the osteogenic differentiation of DPSCs.Overexpression of Sema3A in DPSCs can promote osteogenic differentiation of MC3T3-E1 in the DPSCs/MC3T3-E1 co-culture system.

Objective To explore the differentially expressed mRNAs and related biological processes and pathways in fractional low-dose ionizing radiation (LDIR)-induced senescence of normal human bronchial epithelial (HBE) cells by high-throughput mRNA sequencing and bioinformatics techniques. Methods Senescence-associated β-galactosidase staining and senescence-associated secretion phenotype gene mRNA and protein expression levels were measured at 24 and 48 h after irradiating HBE cells 7 times at doses of 0, 50, 100, and 200 mGy, respectively. The differentially expressed genes were screened by high-throughput sequencing for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Results The senescence-positive area of fractional low-dose irradiated HBE cells increased in a dose-dependent manner (P < 0.05). The mRNA levels and protein expression of transforming growth factor-β1(TGF-β1) and matrix metalloproteinase-9(MMP-9) genes were increased in the 100 mGy × 7 and 200 mGy × 7 groups at 24 and 48 h after the end of irradiation compared with the control group. High-throughput sequencing showed that there were 882, 475, and 1205 differentially expressed mRNAs in each dose group compared with the control group. GO analysis showed that the differentially expressed mRNAs in each dose group were mainly enriched in biological processes such as cell cycle regulation, regulation of nitrogen compound metabolic process, regulation of cell division and response to stimulus. KEGG analysis showed that the differentially expressed mRNAs were mainly enriched in the pathways of cell cycle, cell senescence, and ferroptosis. Conclusion Fractional LDIR induced senescence in HBE cells, and differentially expressed mRNA-associated biological processes and pathways in senescent cells are related to cell cycle and cell senescence.

Objective To investigate the mechanism of fractionated low-dose ionizing radiation (LDIR) in the induction of EA.hy926 cell senescence. Methods EA.hy926 cells were irradiated with X-ray at 0, 50, 100, and 200 mGy × 4, respectively, and cultured for 24, 48, and 72 h. Several indicators were measured, including the levels of cellular senescence-associated β-galactosidase (SA-β-gal) staining, mRNA levels of senescence-associated cell cycle protein-dependent kinase inhibitor genes CDKN1A and CDKN2A, reactive oxygen species (ROS), total antioxidant capacity (T-AOC), and phosphorylated H2A histone family member X (γ-H2AX). Results After 4 fractionated LDIR, compared with the control group, the treatment groups showed increased nucleus area, blurred cell edge, and increased SA-β-gal positive area (P < 0.05) at 24, 48 and 72 h. After 4 fractionated LDIR, the mRNA level of CDKN1A increased in the 100 and 200 mGy × 4 groups at 24 and 48 h (P < 0.05), and CDKN2A mRNA level increased in the 100 and 200 mGy × 4 groups at 48 and 72 h (P < 0.05). The fluorescence intensity of ROS increased in treatment groups at 24, 48, and 72 h after 4 fractionated LDIR (P < 0.05). After 4 fractionated LDIR, the T-AOC level increased in the 100 and 200 mGy × 4 groups at 24 h (P < 0.05), and T-AOC level increased in all treatment groups at 48 and 72 h (P < 0.05). After 4 fractionated LDIR, γ-H2AX fluorescence intensity increased in all treatment groups at 24 h (P < 0.05), and the fluorescence intensity increased in the 100 and 200 mGy × 4 groups at 48 and 72 h (P < 0.05). Conclusion Fractionated LDIR can induce cellular senescence in EA.hy926 cells by impacting the cellular oxidation-antioxidation and oxidative damage levels, and the effects were relatively evident at 100 and 200 mGy.