Objective Platelet-rich plasma (PRP) can promote wound heal ing. To observe the effect of PRP injection on the early heal ing of rat’s Achilles tendon rupture so as to provide the experimental basis for cl inical practice. Methods Forty-six Sprague Dawley rats were included in this experiment, female or male and weighing 190-240 g. PRP and platelet-poor plasma (PPP) were prepared from the heart arterial blood of 10 rats; other 36 rats were made the models of Achilles tendon rupture, and were randomly divided into 3 groups (control group, PPP group, and PRP group), 12 rats for each group. In PPP and PRP groups, PPP and PRP of 100 μL were injected around the tendons once a week, respectively; in the control group, nothing was injected. The tendon tissue sample was harvested at 1, 2, 3, and 4 weeks after operation for morphology, histology, and immunohistochemistry observations. The content of collagen type I fibers also was measured. Specimens of each group were obtained for biomechanical test at 4 weeks. Results All the animals survived till the end of the experiment. Tendon edema gradually decreased and sliding improved with time. The tendon adhesion increased steadily from 1 week to 3 weeks postoperatively, and it was relieved at 4 weeks in 3 groups. There was no significant ifference in the grading of tendon adhesion among 3 groups at 1 week and at 4 weeks (P gt; 0.05), respectively. The inflammatory cell infiltration, angiogenesis, and collagen fibers were more in PRP group than in PPP group and control group at 1 week; with time, inflammatory cell infiltration and angiogenesis gradually decreased. Positive staining of collagen type I fibers was observed at 1-4 weeks postoperatively in 3 groups. The positive density of collagen type I fibers in group PRP was significantly higher than that in control group and PPP group at 1, 2, and 3 weeks (P lt; 0.05), but no significant difference was found among 3 groups at 4 weeks (P gt; 0.05). The biomechanical tests showed that there was no significant difference in the maximal gl iding excursion among 3 groups at 4 weeks postoperatively (P gt; 0.05); the elasticity modulus and the ultimate tensile strength of PRP group were significantly higher than those of control group and PPP group at 4 weeks (P lt; 0.05). Conclusion PRP injection can improve the healing of Achilles tendon in early repair of rat’s Achilles tendon rupture.
Objective Vascular bundle and sensory nerve bundle implantation can promote the osteogenesis of tissue engineered bone. To investigate whether vascular bundle and sensory nerve bundle implantation will affect the expressions of neurokinin 1 receptor (NK1R) and vasoactive intestinal peptide type 1 receptor (VIPR1). Methods Fifty-four 5-montholdNew Zealand rabbits were selected. Autologous bone marrow was aspirated from the posterior il iac spine of rabbits, and the bone marrow mesenchymal stem cells (BMSCs) were prol iferated in vitro. At the 3rd passage, the BMSCs were cultured in the osteogenic culture medium for 7 days. The tissue engineered bone was prepared by the combined culture of these osteoblastic induced BMSCs and β tricalcium phosphate scaffold material. A 1.5 cm segmental bone defect was created at the right femur of rabbits. After the plate fixation, defects were repaired with sensory nerve bundle plus tissue engineered bone (group A, n=18), with vascular bundle plus tissue engineered bone (group B, n=18), and tissue engineered bone only (group C, n=18). X-ray examination was used to evaluate the degree of the ossification. The expression levels of NK1R and VIPR1 were measured by the immuohistochemistry analysis and the mRNA expression of NK1R and VIPR1 by real-time PCR at 4, 8, and 12 weeks after operation. Results The better osteogenesis could be observed in group A and group B than in group C at all time points. X-ray scores were significantly higher in group B than in groups A and C (P lt; 0.05) at 4 weeks, and in groups A and B than in groupC (P lt; 0.05) at 8 and 12 weeks. The mRNA expressions of NK1R and VIPR1 were highest at 8 weeks in groups A and B and gradually decreased at 12 weeks (P lt; 0.05); the expressions were higher in groups A and B than that in group C (P lt; 0.05), and in group B than group A (P lt; 0.05). Immunohistochemistry analysis showed that the expressions of NK1R and VIPR1 were highest at 8 weeks in 3 groups, and the expressions were higher in groups A and B than in group C. Conclusion Implanting vascular bundles into the tissue engineered bone can significantly improve the expression levels of NK1R and VIPR1. It is an ideal method to reconstruct composite tissue engineered bone.
Objective Construction of viable tissue engineered bone is one of the most important research fields in the cl inical appl ication of bone tissue engineering, to investigate the function of nerve factors in bone tissue engineering by celldetection in vitro and construction of neurotization tissue engineered bone in vivo. Methods Fifty-four healthy New Zealandwhite rabbits, male or female, weighing 2-3 kg, were involved in this study. Bone marrow mesenchymal stem cells (BMSCs) from the bone marrow of white rabbits were cultured. The second passage of BMSCs were treated with sensory nerve or motor nerve homogenates, using the LG-DMEM complete medium as control. The prol iferation and osteogenic differentiation of the cells were observed and tested by the MTT assay, alkal ine phosphatase (ALP) stain, and collagen type I immunocytochemistry identification. The osteogenic induced BMSCs were inoculated in β tricalcium phosphate (β-TCP) biomaterial scaffold and cultured for 72 hours, then the β-TCP loaded with seed cells was implanted in the rabbit femur with 15 mm bone and periosteum defects. Fifty-four New Zealand white rabbits were randomly divided into three groups (n=18): sensory nerve bundle (group A) or motor nerve bundle (group B) were transplanted into the side groove of β-TCP scaffold, group C was used as a control without nerve bundle transplantation. X-ray detection was performed at the 4th, 8th, and 12th weeks after operation.