ABSTRACT
Objective To investigate the effect of local injection of phage lyase LysGH 15 into rabbits' knee joint on the systemic inflammation,local infection around knee joint prosthesis and biofilm formation on the prosthesis surface after their knee joint prosthesis implantation surgeries.Methods Models of Staphylococcus aureus infection on rabbits' knee joint prosthesis after prosthesis implantation were built and divided into experimental group for intra-articular injection with lyase and control group for injection with saline into their joint cavity.The phage lysin LysGH15 was synthesized and purified.On the 1st,2nd and 3rd day after the inoculation with Staphylococcus aureus bacteria into the rabbits' knee joint cavity of the prosthesis implanted side,0.5 ml diluted solution of LysGH15 was injected into the knee joint cavity with infection around the prosthesis for the experimental group rabbits and 0.5 ml saline was injected into the corresponding joint cavity for control group rabbits as blank contrast.On the 1st,3rd,7th and 14th day,blood samples were collected from their ear vein to make plasma procalcitonin test for evaluation of rabbits' systemic infection.After the last time for collection of venous blood samples,these rabbits were killed instantly and their knee joints of prosthesis implantation side were dissociated.Tissue around the prosthesis was processed with HE staining to observe and evaluate the local infection and tissue necrosis around the prosthesis.The biofilm formation on the prosthesis surface was evaluated with semi quantitative method after the observation of samples under scanning electron microscope (SEM).Results After the injection of LysGH15 in experimental group,their serum procalcitonin level,which worked as the systemic inflammatory marker,decreased rapidly especially on the 3rd day after lysin injection.Compared with the control group,the infection degree of experimental group significantly decreased.In the experimental group,the infection and necrosis degree of the tissue surrounding the prosthesis were significantly lower in the experimental group than those in the control group.The semi quantitative scores were conducted for these samples and graded to make rank sum test.The difference between the two groups was statistically significant (U=2.4948,P=0.0126).There was a statistically significant difference in the rank sum test between the two groups in the quality of biofilm formation (U=2.2539,P=0.0242).Conclusion Phage lysin LysGH15 can alleviate the rabbits'systemic inflammation caused by Staphylococcus aureus bacteria after their knee joint prosthesis implantation,reduce the extent of damage caused by infection and inflammation to the tissue around the prosthesis,and inhibit the formation of bacterial biofilm on the surface of implanted prosthesis.
ABSTRACT
Objective To investigate the vascular endothelial growth factor (VEGF) expression level by chondrocytes isolated from patients with osteoarthritis (OA) in hip or femoral neck fracture (FNF) and explore the effect of synovial fluid from OA or FNF on secretion of VEGF. Methods The cartilage tissues were collected from 12 patients with OA in hip and 8 patients with FNF. Cartilage was stained with HIM and Safranin O/Fast Green (S/F) method. The damage of cartilage was evaluated using Mankin scores.Cathepsin B which was selected for cell dedifferentiation monitoring marker and VEGF level was detected in the supernatant fluid. The synovial fluid from OA, FNF and DMEM were respectively added to the culture medium to explore their effects on regulating VEGF. Results Cartilage the Mankin scores of OA group were higher than that of FNF group. Chondrocytes gradually lost their original spherical appearance, with Cathepsin B upregulated while VEGF downregulated. The OA synovial fluid can stimulate chongdrocytes to secrete more VEGF than the one from patients with FNF. However, chondrocytes gradually produced less VEGF after passaging. Conclusion Mankin scores had good correlation with chondrocytes' VEGF production in the early stage of primary culture. Chondrocytes showed quick dedifferentiation characteristics in vitro. OA synovial fluid showed abig ger capability in stimulating chondrocytes to express more VEGF, which might indicate that OA synovial fluid participated in the pathological process of OA.
ABSTRACT
Objective To study the role of activated microglia transplantation in recovery of hindlimb locomotor function in rats with spinal cord injury(SCI). Methods A total of 40 female adult Wistar rats were selected and divided into four groups randomly(10 rats in each group).The former two groups were locomotor function observation groups,in which rat model with spinal cord was established by striking with improved self-made Allen's strike equipment to fabricate moderate spinal cord injury and divided into transplantation group and control group.The latter two were histological observation groups,the spinal cord injury model was fabricated by the same above-mentioned method and divided into transplantation and control groups.Before fabricating the spinal cord injury model,the microglia of the newborn rats were cultured,separated,purified and identified and the purity of the microglia determined.The injury position was exposed again seven days after transplantation and the cell suspension of microglia was injected around the injury position with microsyringe,which was free in the control group.The hindlimb locomotor function of rats was detected and scored at 1 day,1,2,3 and 4 weeks in the locomotor function observation groups after transplantation respectively.At the same time,two rats were extracted randomly from the control group and the transplantation group in histological observation groups to cut specimen and slice for Naoumenko-Feign paraffin section and dying.Then,the microglia were observed and counted by microscope and analyzed statistically. Results At 1,2,3 and 4 weeks after operation,the BBB score of the control group and the transplantation group was increased gradually with the time.But compared with the control group,transplantation group had higher scores of hindlimb locomotor function at 2,3 and 4 weeks after operation,with statistical difference(P＜0.05).Naoumenko-Feigin paraffin section and dying and microglia counting showed that positive microglia number in the transplantation group was increased more obviously than the control group,with statistical difference(P＜0.05).Conclusion Activated microglia transplantation can promote the recovery of the hindlimb locomotor function in SCI rats.