| Objective: Magnetic resonance T2-mapping was performed on the model of sheep knee joint cartilage degeneration at different stages,revealing the characteristics and regularity of MRI manifestations of cartilage degeneration in sheep and knee joints at various stages,and analyzing the correlation with the content of proteoglycan in cartilage.Molecular pathological mechanism of variable MRI.Methods: Fifteen healthy Mongolian sheep were randomly divided into group A,group B,group C,group D and group E,with 5 groups in each group.Mongolian sheep were prepared by injecting papain solution into the knee joint.A model of cartilage degeneration in the left knee.Group A was not treated as a control group,and group B,group C,group D,and group E were used as experimental modules.Three injections(1.6 ml each)were performed on day 1,day 4,and day 7,respectively.The modeling is completed.After the first,third,fifth and seventh weeks of modeling,the Siemens Skyra 3.0T magnetic resonance imaging system was used to perform the MRI routine and T2-mapping scans on the Mongolian sheep control group and the left knee joint of the model.Special coil for the knee joint.After scanning,the original data is post-processed on the Syngo.via workstation to obtain the corresponding pseudo color map.The T2 value was measured by the region of interest(ROI)of the medial cartilage of the femoral condyle and the tibial plateau,and the average value was measured three times.After the MRI scan was completed,the knee joint was dissected and taken,and the extracted articular cartilage was subjected to alcian blue-periodic acid sthiff staining(AB-PAS staining),and the cumulative optical density value(IOD)was used to evaluate the content of proteoglycan in the cartilage.And statistical analysis of cartilage T2 value and proteoglycan content by SPSS 20.0 software,P<0.05 was considered to be related.Result: 1.The T2 values of the medial cartilage of the femoral condyle and the tibial plateau of each experimental group were higher than those of the control group.The T2 value of each experimental group was significantly different from that of the control group(P<0.05).With the prolongation of modeling time,the T2 value of the femoral cartilage in the femur increased,and the difference between the two groups was statistically significant(P<0.05).The T2 value of the medial cartilage of the tibial plateau increased,except D.There was no significant difference between the group and the C group(P>0.05),and the other groups had statistically significant differences(P<0.05).2.The evaluation values of proteoglycan content in the medial cartilage of the femoral condyle and tibial plateau of each experimental group were lower than those of the control group.The evaluation value of cartilage proteoglycan content in each experimental group was statistically significant(P<0.05).With the prolongation of modeling time,the expression of proteoglycan in the femoral cartilage of femur was decreased.There was no significant difference between group B and group A and group B and group C(P>0.05).The differences were statistically significant.The expression of proteoglycan in the medial cartilage of the tibial plateau showed a decreasing trend.There was no significant difference between the E group and the D group(P>0.05).Academic significance(P<0.05).3.The scatter plot of the T2 value and proteoglycan content of the femoral condyle cartilage was drawn.The relationship between the two was linear.The Spearman correlation analysis indicated that the T2 value increased and the proteoglycan value decreased.(r =-0.789,P < 0.01).4.The scatter plot of the T2 value and the proteoglycan content of the medial cartilage of the tibial plateau was plotted.The relationship between the two was linear.The Spearman correlation analysis indicated that the T2 value increased and the proteoglycan value decreased.(r=-0.791,P<0.01).Conclusion:1.The T2 value of knee joint cartilage in KOA model was higher than that in the control group,and the T2 value of cartilage in group B,C,D and E gradually increased with the prolongation of modeling time,suggesting that T2-mapping imaging technique can display cartilage.damage.2.With the prolongation of modeling time in KOA model,the content of proteoglycan in cartilage showed a downward trend.The magnetic resonance T2 value of cartilage was negatively correlated with proteoglycan content.T2 value is expected to be noninvasive to reflect the content of proteoglycan in articular cartilage degeneration.Imaging examination indicators are of great significance for diagnosing and monitoring early knee cartilage injury and its biochemical changes,and then guiding clinical treatment. |
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