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BACKGROUND:Currently,there have been studies on the regulatory mechanism of lncRNA\miRNA\mRNA co-expression network on the occurrence and development of osteoarthritis.Our research group has screened qualified NONHSAT248596.1 and miR-146a-5p through the database in the previous stage,but the corresponding in vivo experiments to verify the above regulatory mechanisms are still lacking. OBJECTIVE:To explore the role of NONHSAT248596.1 in regulating competitive endogenous RNA of miR-146a-5p in cartilage degeneration mediated by stromal cell derived factor type 1/chemokine receptor 4 axis in vivo. METHODS:The models of osteoarthritis were established in 36 New Zealand rabbits by injecting stromal cell derived factor 1 solution into the knee joint of the right hind limb.According to the random number table method,they were divided into four groups.lncRNA group,miRNA group,ceRNA group and control group were injected with lentivirus vector overexpressing NONHSAT248596.1,lentivirus vector overexpressing miR-146a-5p,lentivirus vector overexpressing miR-146a-5p+NONHSAT248596.1 and empty lentivirus vector into the molded knee joint,respectively.At 4,8 and 12 weeks of modeling,cartilage tissues and subchondral bone tissues of the knee joint were taken for relevant detection. RESULTS AND CONCLUSION:Hematoxylin-eosin staining and safranin fast green staining showed different degrees of degeneration in the four groups.At 4 weeks,the cartilage tissue of the lncRNA group showed swelling of chondrocytes,loss of cell polarity,destruction of extracellular matrix,surface erosion,fracture formation and partial or full layer loss of cartilage tissue.The degree of cartilage injury was gradually aggravated with time.The progression of articular cartilage inflammation in the miRNA group was the slowest among the four groups.qRT-PCR showed that at the same time point,mRNA expression levels of NONHSAT248596.1,chemokine receptor 4,matrix metalloproteinase 3,matrix metalloproteinase 9 and matrix metalloproteinase 13 in cartilage tissue of the lncRNA group were higher than those of the other three groups(P＜0.05).The mRNA expression levels of miR-146a-5p,aggrecan and type Ⅱ collagen were lower than those of the other three groups(P＜0.05).The mRNA expression levels of NONHSAT248596.1,chemokine receptor 4,matrix metalloproteinase 3,matrix metalloproteinase 9 and matrix metalloproteinase 13 in the miRNA group were lower than those in the ceRNA group and control group at 8 and 12 weeks after the model construction(P＜0.05).The mRNA expressions of miR-146a-5p,aggrecan and type Ⅱ collagen were higher than those of the ceRNA group and control group(P＜0.05).Western blot assay showed that at the same time point,the expression levels of aggrecan and type Ⅱ collagen in cartilage tissue of the lncRNA group were always lower than those of the other three groups(P＜0.05).The expression levels of aggrecan and type Ⅱ collagen in cartilage tissue of the miRNA group at 8 and 12 weeks after modeling were higher than those of the ceRNA group and control group(P＜0.05).The results showed that miR-146a-5p,as the target of NONHSAT248596.1,could be inhibited by the effect of its ceRNA.After acting on miR-146a-5p,NONHSAT248596.1 regulates the stromal cell derived factor type 1/chemokine receptor 4 axis to affect the expression of matrix metalloprotein,type Ⅱ collagen,and aggrecan in osteoarthritis chondrocytes,resulting in the degradation of extracellular matrix and the loss of proteoglycan.
Résumé
BACKGROUND:In recent years,some scholars in the field of tendon bone injury have attached stromal cell-derived factor 1 to tissue engineering scaffolds to promote tendon bone healing,and achieved good results.However,whether stromal cell-derived factor 1 promotes tendon bone healing mechanisms and participates in the repair of natural healing has not yet been defined. OBJECTIVE:To study the expression of stroma-cell derived factor 1 during tendon bone healing after rupture of the whole supraspinatus muscle of the rabbit rotator cuff and its migration effect and optimal in vitro migration promoting concentration on stem cells during tendon bone injury. METHODS:Totally 18 adult New Zealand rabbits were randomly selected to establish rotator cuff injury models,and an additional 3 rabbits were selected as blank controls.At 3,5,7,14,21,and 28 days after modeling,three rabbits were executed separately and the rabbits in the blank group were sacrificed.The tissues of tendon bone junction were taken and stored in a-80℃refrigerator.The expression of stromal cell-derived factor 1 was detected by ELISA at each time point after injury.Mesenchymal stem cells were isolated from the bone marrow of young rabbit femur,cultured,and identified.Transwell assay was performed to verify the migration-promoting effect of stromal cell-derived factor 1 on stem cells and the optimal migration-promoting concentration in vitro.The stem cells cultured to P3 were co-cultured with BrdU and injected into the rabbit ear marginal vein,and immunohistochemical staining was used to verify whether the stem cells migrated to the injury site. RESULTS AND CONCLUSION:(1)Stromal cell-derived factor 1 gene expression was bimodal during rotator cuff tendon bone healing.Stromal cell-derived factor 1 gene expression increased significantly at 3 days post-injury(P<0.01)and then decreased,reaching a minimum at 5 days post-injury.It increased again and reached a peak 14 days after injury(P<0.01)and then decreased.(2)Cell immunohistochemical staining displayed that stem cells labeled with BrdU did migrate to the injury site.(3)The results of the transwell experiment exhibited that 60-80 ng/mL stromal cell-derived factor 1 had the best effect on promoting migration of stem cells,while a concentration of 200 ng/mL inhibited migration.(4)Stromal cell-derived factor 1 is involved in the healing of rotator cuff tendon bone during the inflammatory response phase and the proliferation phase.The mechanism of action may be to promote the migration of stem cells to the injury and their differentiation into various types of cells to promote repair.In addition,the pro-migration effect of stromal cell-derived factor 1 exists at a range of concentrations,beyond which it may act as an inhibitor.
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BACKGROUND:As a dominant breed pig in southwest China,the southern Yunnan small-ear pig has been widely used as an experimental animal in the basic research of other disciplines,but there are still no reports on its application in anterior cruciate ligament reconstruction. OBJECTIVE:To establish a large animal model of the southern Yunnan small-ear pig with anterior cruciate ligament with autologous Achilles tendon was established. METHODS:Twenty adult female Yunnan small-ear pigs were equally randomized into two groups.In the autologous Achilles tendon group,the right knee anterior cruciate ligament was reconstructed with autologous Achilles tendon as a graft,while in the sham-operated group,a similar operation was performed on the right knee without any treatment of the anterior cruciate ligament.General conditions of each pig were observed and recorded before and 12 months after surgery.Ligaments and grafts were taken for gross observation and MAS scoring.Hematoxylin-eosin staining was performed to observe morphological characteristics of ligaments.The staining and arrangement of type I and type Ⅲ collagen were evaluated by immunohistochemistry.Transmission electron microscopy was used to observe the type,size,diameter,ratio,and distribution of collagen fibers in ligaments. RESULTS AND CONCLUSION:All animals had normal diet and activity,good wound healing,no obvious inflammatory reaction,no local purulent infection,and no significant changes in mental and urinary conditions compared with those before surgery.The reconstructed cruciate ligament of the knee was intact,with no stiffness and normal range of motion.Both the anterior drawer and Lachman tests were negative.Gross observation of the graft:12 months after surgery,the grafts was in good position,with good integrity,obvious tension,ligament color close to the original anterior cruciate ligament,and complete surface synovial coverage.Most of the intraarticular ligaments in the autologous Achilles tendon group were defined as MAS I type and a few were defined as MAS Ⅱ type.In the sham-operated group,the intraarticular ligament was defined as MAS I type.Hematoxylin-eosin staining indicated that,12 months after surgery,collagen fibers in the autologous Achilles tendon group began to appear bundled,isotropic,and uniformly arranged,with more obvious isotropic corrugations,and the nuclei were mainly linear or spindle-shaped,which were similar to those in normal anterior cruciate ligament tissue of the sham-operated group.Immunohistochemistry results indicated that,12 months after surgery,there was a higher expression of type I collagen and significantly less expression of type Ⅲ collagen in the reconstructed anterior cruciate ligament in the autologous Achilles tendon group.The degree of type I and type Ⅲ staining was similar in the two groups.Under the transmission electron microscope,the diameter,arrangement and density of collagen fibers in the reconstructed anterior cruciate ligament of the autologous Achilles tendon group were similar to those of the original anterior cruciate ligament at 12 months after surgery,indicating that the ligament remodeling process had been basically completed in the autologous Achilles tendon group at 12 months after surgery.Through a comprehensive evaluation of animal general conditions,ligament general view,MAS score,hematoxylin-eosin staining,immunohistochemistry,and transmission electron microscopy observation,we successfully established a large animal model of anterior cruciate ligament reconstruction using autogenous Achilles tendon in southern Yunnan small-ear pigs,with good morphological,histological and ultrastructural results.
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OBJECTIVE@#To investigate the feasibility of establishing an anterior cruciate ligament (ACL) reconstruction model using hamstring tendon autograft in cynomolgus monkeys.@*METHODS@#Twelve healthy adult male cynomolgus monkeys, weighing 8-13 kg, were randomly divided into two groups ( n=6). In the experimental group, the ACL reconstruction model of the right lower limb was prepared by using a single bundle of hamstring tendon, and the ACL of the right lower limb was only cut off in the control group. The survival of animals in the two groups was observed after operation. Before operation and at 3, 6, and 12 months after operation, the knee range of motion, thigh circumference, and calf circumference of the two groups were measured; the anterior tibial translation D-value (ATTD) was measured by Ligs joint ligament digital body examination instrument under the loads of 13-20 N, respectively. At the same time, the experimental group underwent MRI examination to observe the graft morphology and the signal/ noise quotient (SNQ) was caculated.@*RESULTS@#All animals survived to the end of the experiment. In the experimental group, the knee range of motion, thigh circumference, and calf circumference decreased first and then gradually increased after operation; the above indexes were significantly lower at 3 and 6 months after operation than before operation ( P<0.05), and no significant difference was found between pre-operation and 12 months after operation ( P>0.05). In the control group, there was no significant change in knee range of motion after operation, showing no significant difference between pre- and post-operation ( P>0.05), but the thigh circumference and calf circumference gradually significantly decreased with time ( P<0.05), and the difference was significant when compared with those before operation ( P<0.05). At 6 and 12 months after operation, the thigh circumference and calf circumference were significantly larger in the experimental group than in the control group ( P<0.05). At 3 and 6 months after operation, the knee range of motion was significantly smaller in the experimental group than in the control group ( P<0.05). Under the loading condition of 13-20 N, the ATTD in the experimental group increased first and then decreased after operation; and the ATTD significantly increased at 3, 6 months after operation when compared with the value before operation ( P<0.05). But there was no significant difference between the pre-operation and 12 months after operation ( P>0.05). There was no significant change in ATTD in the control group at 3, 6, and 12 months after operation ( P>0.05), and which were significantly higher than those before operation ( P<0.05). At each time point after operation, the ATTD was significantly smaller in the experimental group than in the control group under the same load ( P<0.05). The MRI examination of the experimental group showed that the ACL boundary gradually became clear after reconstruction and was covered by the synovial membrane. The SNQ at each time point after operation was significantly higher than that before operation, but gradually decreased with time, and the differences between time points were significant ( P<0.05).@*CONCLUSION@#The ACL reconstruction model in cynomolgus monkey with autogenous hamstring tendon transplantation was successfully established.