Effect study of exosomes derived from platelet-rich plasma in the treatment of knee cartilage defects in rats.

BACKGROUND: The repair of articular cartilage defects has always been a difficult problem. We aimed to investigate the therapeutic effect of intra-articular injection of platelet-rich plasma (RPR) and PRP-derived exosomes (PRP-Exos) on cartilage defects in rat knee joints and then provide experience for the use of PRP-exos in cartilage defect repair. METHODS: Rat abdominal aortic blood was collected, and PRP was extracted by two-step centrifugation. PRP-exos were obtained by kit extraction, and PRP-exos were identified by various methods. After the rats were anesthetized, a cartilage defect subchondral bone was created at the proximal end of the origin of the femoral cruciate ligament with a drill. SD rats were divided into 4 groups, including PRP group, 50 µg/ml PRP-exos group, 5 µg/ml PRP-exos group, and control group. One week after the operation, 50 µg/ml PRP, 50 µg/ml PRP-exos, 5 µg/ml PRP-exos and normal saline were injected into the knee joint cavity of rats in each group, once a week. A total of two injections were given. On the 5th and 10th week after drug injection, the serum levels of matrix metalloproteinase 3 (MMP-3) and tissue inhibitor of matrix metalloproteinase 1 (TIMP-1) were detected by each treatment method, respectively. The rats were killed at the 5th and 10th weeks, respectively, and the cartilage defect repair was observed and scored. The defect repair tissue sections were used for HE staining and type II collagen immunohistochemical staining. RESULTS: The histological results showed that both PRP-exos and PRP could promote cartilage defect repair and type II collagen formation, and the promoting effect of PRP-exos was significantly better than that of PRP. In addition, enzyme-linked immunosorbent assay (ELISA) results showed that compared with PRP, PRP-exos could significantly increase serum TIMP-1 and decrease serum MMP-3 in rats. And the promoting effect of PRP-exos was concentration dependent. CONCLUSION: Intra-articular injection of PRP-exos and PRP can promote the repair of articular cartilage defects, and the therapeutic effect of PRP-exos is better than the same concentration of PRP. PRP-exos are expected to be an effective treatment for cartilage repair and regeneration.

A systematic review of p53 as a biomarker of survival in patients with osteosarcoma.

Osteosarcoma is the most common malignant bone tumor, and the prognosis of patients with osteosarcoma is still unsatisfactory with low survival rates. There are many studies assessing the prognostic role of upregulated p53 in patients presenting osteosarcoma, and there is no consistent finding. To summarize the existing evidence about whether the presence of upregulated p53 was a biomarker of survival in patients with osteosarcoma, we performed a systematic review and meta-analysis of relevant publications. We assessed the effect of upregulated p53 on the 3-year overall survival and the 3-year disease-free survival by calculating the pooled odds ratio (OR) with corresponding 95% confidence interval (95%CI). Fifteen studies with a total of 609 patients with osteosarcoma were finally included into the systematic review and meta-analysis. Compared with osteosarcoma patients with low or undetectable p53, patients with upregulated p53 were obviously associated with decreased 3-year overall survival (OR = 0.29, 95 %CI 0.19-0.43, P < 0.001). In addition, patients with upregulated p53 were obviously associated with decreased 3-year disease-free survival (OR = 0.06, 95 %CI 0.02-0.23, P < 0.001). The results from the systematic review and meta-analysis highlight that p53 is an effective biomarker of survival in patients with osteosarcoma. In addition, more studies with a large sample size are needed to identify the effect of p53 expression in osteosarcoma patients.

Controlled release of transforming growth factor-beta receptor kinase inhibitor from thermosensitive Chitosan-based hydrogel: application for prevention of capsular contracture.

BACKGROUND: Capsular contracture has become the most common complication associated with breast implant. Transforming growth factor-beta (TGF-ß) is well known for a prominent role in fibrotic diseases. Due to the critical role of TGF-ß in pathogenesis of capsular formation, we utilized thermosensitive C/GP hydrogel to controlled release of TGF-ß receptor kinase inhibitor (SD208) and investigated their effects on capsular contracture. METHODS: In vitro degradation and drug release of C/GP hydrogel were performed. Twenty-four rabbits underwent subpanniculus implantation with 30 ml smooth silicone implants and were randomly divided into four groups as follows: Group 1 received saline solution; Group 2 received SD208; Group 3 received SD208-C/GP; Group 4 received C/GP. At 8 weeks, the samples of capsular tissues were analyzed by hematoxylin and eosin and immunohistological staining. The mRNA expression of collagen III and TGF-ß1 was detected by RT-PCR assay. RESULTS: C/GP hydrogel could be applied as an ideal drug delivery vehicle which supported the controlled release of SD208. SD208-C/GP treatment showed a significant reduction in capsule thickness with fewer vessels. The histological findings confirmed that the lower amounts of inflammatory cells and fibroblasts infiltrate in SD208-C/GP group. In contrast, typical capsules with more vessel predominance were developed in control group. We did not observe the same inhibitory effect of SD208 or C/GP treatment on capsular contracture. Moreover, SD208-C/GP therapy yielded an evident down-regulation of collagen III and TGF-ß1 mRNA expression. CONCLUSIONS: This study demonstrated that controlled release of TGF-ß receptor kinase inhibitor from thermosensitive C/GP hydrogel could significantly prevent capsule formation after mammary implants.

Statins induce immunosuppressive effect on heterotopic limb allografts in rat through inhibiting T cell activation and proliferation.

Long-term use of immunosuppressive agents could bring many side effects. Recently, 3-Hydroxy-3-methyl-gutaryl coenzyme A reductase inhibitors (statins) have been reported to be immunomodulatory besides lowering serum cholesterol level. The aim of this study was to investigate the effects of statins on composite tissue allografts and T lymphocyte in vivo and in vitro. Rats were divided into 5 groups: syngeneic transplantation group (Lewis-Lewis); allogeneic control group (Brown Norway-Lewis, no treatment); low-dose statins group (15 mg /kg); high-dose statins group (30 mg /kg) and cyclosporin A group. In vivo, treatment of statins significantly prolonged allografts survival as compared to control group. Histological findings further supported these clinical results and demonstrated less extent of rejection. Immunohistochemical analysis showed that there was a remarkably reduced T cells infiltration in statins groups. Moreover, the serum levels of IL-2 and IFN-gamma were decreased after statins therapy, while these in control group increased significantly. Meanwhile, transcriptional activities of IL-2 and IFN-gamma were also dramatically down-regulated after statins treatment. In vitro, mixed lymphocyte reaction assay was performed and the results revealed lymphocyte proliferation was inhibited by statins in a dose-dependent manner. Furthermore, administration of statins exhibited inhibitory effects on CD3/CD28 mediated T cell activation and proliferation. Besides, the results demonstrated that statins significantly down-regulated mRNA expression and suppress cytokine production of IL-2 and IFN-gamma in vitro. In conclusion, our data demonstrated that application of statins could induce immunosuppressive effect and prolong allografts survival through inhibiting activation and proliferation of T cell and reducing production of IL-2 and IFN-gamma.

[Combined use of autologous micro-morselized bone with bone morphogenetic protein and type I collagen graft in repairing rabbit bone defects].

OBJECTIVE: To study the effect of combined use of autologous micro-morselized bone with bone morphogenetic protein(BMP) and type I collagen graft on the treatment of segmental bone defects. METHODS: The bulk bone of rabbit iliac crest was ground into micro-morselized bone, which was combined with BMP and type I collagen. The model of 1.5 cm bone defect was established in the middle shaft of the radius. Fifty-six rabbits were assigned to four repairing methods: autologous micro-morselized bone graft with BMP and type I collagen, autologous micro-morselized bone graft with type I collagen, autologous micro-morselized bone graft alone, and control group. The defect-repairing capability of each group was assessed by radiographic, histological, bone densitometry and biomechanical studies. RESULTS: X-ray manifested that at the end of 8 weeks after operation, the bone defect treated with autologous micro-morselized bone graft with BMP and type I collagen was repaired completely, and at the end of 12 weeks after operation the bone defect treated with autologous micro-morselized bone and type I collagen was cured completely, but the bone defect treated with autologous micro-morselized alone was completely repaired. No healing was found in the control group. In the bone densitometry detection, the material with BMP exhibited the strongest defect-repairing capability in terms of amount increased and quality of the new bone at the end of 8 weeks and 12 weeks. The group with BMP has the best mechanical strength of all groups at the end of 12 weeks. CONCLUSION: Autologous micro-morselized bone graft with BMP/type I collagen and autologous micro-morselized bone graft with type I collagen prove to be effective in repairing segmental bone defects. The autologous micro-morselized bone combined BMP and type I collagen is an excellent bone repairing material considering the satisfactory osteogenesis, osteo-conduction, and osteo-induction seen in this method.