Liangquan Peng

Experimental Study of Nano-Hydroxyapatite/Recombinant Human Bone Morphogenetic Protein-2 Composite Artificial Bone

Abstract Objective: To investigate the repairing ability of nano-hydroxyapatite/recombinant human bone morphogenetic protein-2 (Nano-HA/rhBMP-2) composite artificial bone for bone defect and to provide evidence for its application in clinical repair of bone defect. Methods: The animal model of bone defect was made on unilateral radius of 90 New Zealand white rabbits, which were randomly divided into experimental group (group A, bone defect was repaired with Nano-HA/rhBMP-2 composite artificial bone), control group (group B, bone defect was repaired with Nano-HA artificial bone), and blank group (group C, bone defect was unrepaired). The repairing ability for bone defect was evaluated by gross observation, X-ray examination, scanning electron microscope, radionuclide bone imaging and biomechanical analysis at 4th, 8th, and 12th week postoperatively. Results: Both Nano-HA/rhBMP-2 composite artificial bone and Nano-HA artificial bone could stimulate new bone formation, but the former could stimulate more new bone formation and had better repairing ability for bone defect than that of the latter, with statistically significant difference (P <0.05). Conclusion: Nano-HA/rhBMP-2 composite artificial bone has good repairing ability for bone defect and it is hopeful to become an ideal repairing material for bone defect.

Placement of Double Tunnels in ACL Reconstruction Using Bony Landmarks Versus Existing Footprint Remnant A Prospective Clinical Study With 2-Year Follow-up

Background: The outcomes of double-bundle anterior cruciate ligament reconstruction (DB-ACLR) are becoming controversial. One of the main reasons for the controversy is the techniques for bone tunnel placement. The common technique to place the bone tunnels is to use bony landmarks, while a new approach uses footprint remnants. Purpose: To investigate if placement of double tunnels using bony landmarks produces the same clinical results as that of using existing footprint remnants. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: A total of 72 male patients were randomly divided into 2 groups of 36 patients each: (A) DB-ACLR tunnel placement using the footprint remnant procedure (EF group) and (B) DB-ACLR tunnel placement using the bony landmark procedure (BL group). All patients were evaluated before and after surgery. Outcomes were measured by KT-2000 arthrometer side-to-side difference, pivot-shift test, and Tegner, Lysholm, and International Knee Documentation Committee (IKDC) scores. Second-look arthroscopic evaluations were performed in 59 cases (28 and 31 cases in the EF and BL groups, respectively). Results: The mean follow-up time was 36.9 ± 4.8 months. Postoperative 3-dimensional computed tomography scans showed that bone sockets were variable on both femoral and tibial sides in the EF group and almost consistent in the BL group. All of the evaluation indexes were significantly improved postoperatively in both groups. There were no revision cases in the EF group and 2 in the BL group. The EF group showed a faster range of motion (ROM) recovery (at 0° to 120°) than did the BL group. At final follow-up, there was no significant difference between the EF and BL groups in Tegner score (5.88 ± 1.39 vs 5.16 ± 1.76; P = .058) or pivot-shift test (34 vs 32; P = .067). The EF group had a larger proportion of patients with IKDC grade A (normal) (33 vs 24; P < .020), smaller side-to-side difference (0.68 ± 0.38 mm vs 1.23 ± 0.61 mm; P < .001), higher Lysholm score (91.29 ± 4.90 vs 88.71 ± 5.09; P = .032), and better second-look arthroscopic evaluations for graft quality in the anteromedial (P = .034), posterolateral (P = .015), and combined bundles (P = .029) compared with the BL group. Conclusion: Although both techniques provided satisfactory clinical results, DB-ACLR using the existing footprint remnant for tunnel placement showed better functional results with respect to faster ROM recovery, higher subjective outcome scores, and better arthroscopic second-look with no revision cases.

DNA Methylation Profiling in Chondrocyte Dedifferentiation In Vitro

DNA methylation has emerged as a crucial regulator of chondrocyte dedifferentiation, which severely compromises the outcome of autologous chondrocyte implantation (ACI) treatment for cartilage defects. However, the full‐scale DNA methylation profiling in chondrocyte dedifferentiation remains to be determined. Here, we performed a genome‐wide DNA methylation profiling of dedifferentiated chondrocytes in monolayer culture and chondrocytes treated with DNA methylation inhibitor 5‐azacytidine (5‐AzaC). This research revealed that the general methylation level of CpG was increased while the COL‐1A1 promoter methylation level was decreased during the chondrocyte dedifferentiation. 5‐AzaC could reduce general methylation levels and reverse the chondrocyte dedifferentiation. Surprisingly, the DNA methylation level of COL‐1A1 promoter was increased after 5‐AzaC treatment. The COL‐1A1 expression level was increased while that of SOX‐9 was decreased during the chondrocyte dedifferentiation. 5‐AzaC treatment up‐regulated the SOX‐9 expression while down‐regulated the COL‐1A1 promoter activity and gene expression. Taken together, these results suggested that differential regulation of the DNA methylation level of cartilage‐specific genes might contribute to the chondrocyte dedifferentiation. Thus, the epigenetic manipulation of these genes could be a potential strategy to counteract the chondrocyte dedifferentiation accompanying in vitro propagation. J. Cell. Physiol. 232: 1708–1716, 2017.

Gene expression profile of the synovium and cartilage in a chronic arthritis rat model.

Abstract: Background: Primary osteoarthritis (OA) is a polygenic disease. To investigate the gene expression profile of cartilage and synovium from osteoarthritis and healthy rats using cDNA microarray is beneficial to recognize the pathogenesis of osteoarthritis and provide evidence for gene therapy of osteoarthritis. Objective: The present study aimed to investigate the gene expression profile of the cartilage and synovium of chronic arthritis and healthy rats through cDNA microarray assay, and identify the differentially expressed genes. This study may be helpful for understanding the role of differentially expressed genes in osteoarthritis and the gene polymorphism of osteoarthritis. Methods: A total of 24 male Wistar rats were randomly divided into control group and osteoarthritis group (n = 12 per group). The synovial and cartilage were obtained and total RNA was extracted. cDNA microarray assay was performed to identify the differentially expressed genes, and cluster analysis was conducted. Results and Conclusion: A total of 82 differentially expressed genes were identified, among which 27 were up-regulated and 55 down-regulated. Gene microarray assay is effective to identify differentially expressed genes and may find out novel osteoarthritis associated genes. Multiple genes are involved in the pathogenesis of osteoarthritis. The differentially expressed genes provide important information for further studies on the pathogenesis of osteoarthritis and gene therapy of osteoarthritis.

Mutagenicity test of magnetic nanocomposite for interface fixation

The aim of the study is to evaluate the biocompatibility and safety of the Nano-HA/PLLA/Fe2O3 magnetic composites material from toxicological aspects for the clinical use of the interface fixation, produce the Nano-HA/PLLA/Fe2O3 magnetic composites material and its diffusion, and examine the diffusion through Ames test. The observation markers of the test are the mutagenic rates (MRs) of murine typhoid salmonella. The results of MR are less than 2 in the experimental groups of all dosage levels. The Nano-HA/PLLA/Fe2O3 magnetic composites material will not cause the increase of the back mutation in the MTS. It indicates that this artificial bone will not cause gene mutation.

Femoral footprint variation of the posterolateral bundle of the anterior cruciate ligament and double-bundle reconstruction.

BACKGROUND The study is aimed to observe the range of variation of the ACL PLB femoral footprint and investigate countermeasures for accurate femoral bone tunnel placement during double-bundle ACL reconstruction. METHODS The femoral insertions of the anteromedial bundle (AMB) and PLB of the ACL were dissected in 30 male cadaveric knees. The ACL footprint on the lateral intercondylar wall (LIW) was observed, and the shape of the LIW, the resident ridge, the angle between the ACL long axis and femoral axis (AA), and the vertical distance from the center of the PLB to the lowest cartilage border of the LIW (PD) were measured. RESULTS The area most populated by the ACL fibers was directly under the resident ridge. AA = 18.7°±15.25° with variation from -18° to 56°, and PD=7.02±1.47 mm with variation from 3.75 to 11.08 mm. Both discrete values were very large in both groups of data. There were two kinds of LIW: trapezoidal (8 knees) and triangular (21 knees). Both AA and PD values exhibited significant differences between the two types of LIWs (P=0.00). CONCLUSION AA and PD vary among individuals. The insertions and centers of the PLB cannot be exactly anatomically determined with one size. For double-bundle ACL reconstruction, an individualized intraoperative footprint observation for fresh cases with footprint remnants, or resident ridge and anteromedial bundle-interval identification for old ACL tears, can be reasonable methods for posterolateral tunnel orientation. CLINICAL RELEVANCE Clinical relevance is observe the range of variation of the PLB femoral footprint for clinical double-bundle ACL reconstruction.