ABSTRACT
Objective To investigate the effect of cyclic tensile stress (CTS) on the metabolism inand apoptosis of rat chondrocytes.Methods Primary rat chondrocytes were cultured on a Bioflex plate for one day and then stretched cyclically for 24 hours at a frequency of 0.5 Hz using a Flexcell-5000T apparatus.The cells were divided into 5 groups according to their stretching ratio:0％ (the control group),2％,6％,10％ and 14％.After the stretching,Col Ⅱ,Aggrecan,MMP-13 and ADAMTS-5 mRNA were measured using qPCRs,and the NO and PGE2 levels were measured using ELISA kits.Moreover,TUNEL staining and Annexin V-FITC/PI were used to analyze the apoptosis of chondrocytes.Results Compared with the control group,the average levels of Col Ⅱ and Aggrecan mRNAdecreasedin 10％ and 14％ groups [(0.738±0.11) and (0.58±0.13),(0.75±0.11) and (0.55±0.09)].In those groups,the MMP-13 [(2.47±0.47) and (2.88±0.36)] and ADAMTS-5 mRNA level [(2.39±0.33) and (2.75±0.49)],the NO [(6.96±0.96) and (8.28±0.82)] and PGE2 level [(6.83±0.66) and (7.15±0.71)] had increased significantly.In the 6％ group the average levels of Col Ⅱ(1.76±0.30) and Aggrecan mRNA (1.93±0.14)of 6％ group were significantly higher than the control group,but the NO level of the former (3.07±0.20) was significantly lower than the control group (3.89 ± 0.33).The apoptosis rate of chondrocytesin 2％ and 6％ groups were (0.065±0.013) and (0.063 ± 0.147),without significant differences to that of the control group (0.045 ± 0.008).However,compared with the control group,apoptosis in the 10％ and 14％ groups [(0.135 ±0.026) and (0.184±0.020)] increased significantly.Conclusion The effect of cyclic tensile stress on chondrocyte metabolism and apoptosis was magnitude-dependent.Ten percent and 14％ CTS can increase the catabolism and apoptosis of chondrocytes.Ten percent and 14％ strain can increase the catabolism and apoptosis of chondrocytes.Cyclic 6％ strain can increase the anabolism of chondrocytes,but 2％ strain has no impact on metabolism or apoptosis.
ABSTRACT
Objective To evaluate the diagnostic value of MSCT longitudinal reconstruction in the ureteral obstruction.Methods 34 patients with ureteral obstruction were scaned transversely and longitudinally by GE Lightspeed 16 CT scanner and the images were reconstructed with three-dimensional software.All cases were proved by operation and pathology except for 2 cases of uretal obstruction compressed by retroperitoneal lymph nodes.Results In 34 cases,there were 22 cases of ureteral calculi,2 cases of ureteritis,3 cases of carcinoma of ureter,3 cases of pelvisureteral conjunction stricture,1 case of ureteral cyst,1 case of retrocaval ureter and 2 cases of ureter compressed by retroperitoneal metastatic lymph nodes.On longitudinal reconstruction images,22 lesions of calculi in the ureter and thickened uretal wall were showed.Contrast-enhanced CT scan was preformed in 5 cases,the CT values of lesions were increased about 20~35 HU,after administration of contrast medium,and light hydronephrosis in 18 cases,medium hydronephrosis in 6,serious hydronephrosis in 2 and no hydronephrosis in one case were showed on delayed contrast-enhanced scan.Conclusion Longitudinal reconstruction image is of significant value in diagnosis of ureteral obstruction.