Experimental Study On The Relationship Between Apoptosis And JAK1/STAT1 Signal Pathway In DDH

Objective To investigate the relationship between JAK1/STAT1 signal transduction pathway and apoptosis in acetabular dysplasia with developental disocation of hip joint(DDH).Methods Thirty 28-day-old New Zealand white rabbits,male and female,were randomly divided into experiental group(n=20)and control group(n=10).In the experimental group,the right hindlimb of rabbits was fixed with tubular polymer plastic for 8 weeks to make DDH model.The fixed right hindlimb was used as the experimental side,while the control group was fed the same,and the right hindlimb was not treated as control.After 8 weeks,the acetabular index,the degree of dislocation of femoral head and the continuity of Shenton line were used to judge the model.Nine successful rabbits and nine control rabbits were randomly selected.the experimental hind limbs and normal hind limbs were dissected respectively.the overall morphological changes of hip joint were observed.the acetabular cartilage was made into HE specimens and the appropriate visual field was selected under microscope.The changes of chondrocytes were observed as a whole.The expression of p-STAT1,p-JAK1,Caspase-3,Bcl-2 and Bax in chondrocytes of experimental group and control group were detected by immunohistochemical special antigen antibody binding method.The expression of STAT1,p-STAT1,JAK1,p-JAK1,Caspase-3,Bcl-2 and Bax in chondrocytes was detected by Western blot(Western Blot).TUNEL assay was used to detect whether there was apoptosis in acetabular cartilage and the degree of apoptosis.Paired samples were analyzed by paired t test and univariate analysis of variance to discuss the correlation between apoptosis,apoptosis related factors and acetabular cartilage dysplasia.Results The main results were as follows:(1)there were significant differences in acetabular morphology between the experimental group and the control group.the femoral head was dislocated outwards and upward,the acetabular pelvis lip on the experimental side was varus,the shape was thicker than that of the control side,the contour of acetabulum and femoral head was abnormal and the binding relaxation was not tight.The round ligament is abnormally thick and relaxed,and the whole is unstable;the surface color of articular cartilage changes obviously,showing abnormal yellow shape,the touch is uneven,and scattered ulcer can be seen.(2)after HE staining,the chondrocytes in each control group were in good shape and arranged neatly.In the experimental group,the shape and size of the cells in the cartilage were different,vacuoles appeared,the arrangement of middle cells was disordered,the number of mast cell layer cells decreased,the arrangement was irregular,the normal columnar structure was lost,and a few clusters of chondrocytes could be seen.Cartilage matrix increased.(3)the acetabular index of the experimental group was significantly higher than that of the control group(P<0.05).(4)Immunohistochemical detection of p-STAT1,p-JAK1,Caspase-3,Bax showed that the average gray level of the experimental group was higher than that of the control group(P<0.05),Bcl-2 results the average gray level of the experimental group was lower than that of the control group(P<0.05),and there was significant difference between the experimental group and the control group.(5)the results of STAT1,p-STAT1,JAK1,p-JAK1,Caspase-3,Bax detected by Western blot in the experimental group were higher than those in the control group(P<0 05),the Bcl-2 and the ratio of Bcl-2/Bax in the experimental group was lower than that in the control group(P<0 05).It's statistically significant.(6)the results of TUNEL assay showed that the apoptosis rate of the experimental group was significantly different from that of the control group.Conclusion The main results are as follows:(1)the abnormal expression of apoptosis-related factors in acetabular cartilage can be caused by dislocation or subluxation of hip joint,and the abnormal expression of each factor may lead to acetabular cartilage dysplasia.(2)JAK1/STAT1 signaling pathway is abnormally expressed in the process of acetabular cartilage dysplasia,and its abnormal activation and expression may lead to the abnormal expression of apoptosis factors downstream,which leads to and aggravates the progress of acetabular cartilage dysplasia.