| Objectives To study the effect of IGFBP-4 on pain in the mouse model of knee osteoarthritis induced by iodoacetic acid.Methods Knee Osteoarthritis was induced by intra-articular injection of iodoacetic acid.Normal saline was injected into knee joint cavity as C57 blank control(C57 control group).IGFBP-4 transgenic mice were used instead of establishing model by drug.C57 mice were used as control.General osteoarthritis model group(C57 OA group),IGFBP-4 transgenic osteoarthritis model group(IGFBP-4 OA group)and IGFBP-4 transgenic blank control group(IGFBP-4 control group)were established.The following operations were performed:1.Observe the morphological changes of mice after modeling and measure the diameter of knee joint with vernier caliper.2.The changes of synovium and articular cartilage in articular cavity were observed by stereomicroscope.3.Von Frey filament test was used to obtain the sensitivity changes of different groups of mice to mechanical pain stimulation.4.The hot plate experiment was used to observe the changes of mice’s sensation of heat pain in different groups.5.Hematoxylin-eosin(HE)staining was used to observe the injury of synovium and cartilage of knee joint.6.Immunohistochemical method was used to detect the expression of IGFBP-4 in synovium of knee joint of mice in different groups.7.The expression of IGFBP-4 and PENK in synovium of joint was detected by Western blot.Results 1.OA The mice in OA group showed dim hair color,decreased activity,thin stool and decreased diet.Compared with C57 control group,the knee joint swelling in C57 OA group was serious,and the joint diameter was quite different(P<0.001).Compared with IGFBP-4 control group,IGFBP-4OA group had more swelling of knee joint and a larger difference in knee joint diameter(P<0.001).Compared with IGFBP-4OA group,the swelling degree of C57 OA group was significantly different,and the knee joint diameter was significantly different(P<0.05).There is no significant difference in knee joint diameter between C57 control group and IGFBP-4 control group,P>0.05,and there is no statistical difference.2.Observe by stereomicroscope: Knee joint of normal C57 mice is tight;The synovium is smooth,bright and yellowish,and the cartilage is flat.In OA group of IGFBP-4 transgenic mice,synovium proliferated,its volume became larger,and a few defects on cartilage surface were found.In C57 OA group,synovium hyperplasia was serious,synovial fluid increased and cartilage surface defect was serious.In IGFBP-4 control group,the synovium was smooth and continuous,and the cartilage surface was the most complete and smooth.3.On the 7th day,the threshold of mechanical pain in C57 OA group began to decrease,and it was significantly different from that in C57 control group on the 28 th day(P<0.001).On the 14 th day,the threshold of mechanical pain in IGFBP-4OA group began to decrease,and there was a big difference between IGFBP-4oa group and igfbp-4 control group on the 28 th day(P<0.001).Compared with IGFBP-4 OA group,the threshold of mechanical pain in C57 OA group was significantly different(P<0.001).4.The hot pain threshold in C57 OA group began to decrease obviously on the first day after modeling and continued to decrease on the 28 th day,which was significantly different from that in C57 control group(P<0.001).The hot pain threshold of IGFBP-4 OA group changed on the 14 th day,decreased obviously,and decreased continuously on the 28 th day,which was significantly different from that of C57 control group(P<0.001).There is a difference between C57 control group and IGFBP-4 control group in the change of hot pain threshold within 28 days,(P<0.05),which has statistical significance.5.HE staining: Synovial cells in C57 control group were spindle-shaped,with loose arrangement,tight fine spines,complete network of intercellular connections,tight arrangement of chondrocytes,many layers of cells,smooth surface,and no obvious cavities and defects.In IGFBP-4OA group,synovial cells were spindle-shaped,loosely arranged,with disordered intercellular connections and uneven cartilage surface.compared with C57 control group,the number of chondrocytes decreased slightly,and a few defects were found.In C57 OA group,synovial cells were irregular in shape,disordered in arrangement,not tightly connected with fine spines,disordered in connected network structure,and uneven in cartilage surface.compared with IGFBP-4OA group,the number of chondrocytes decreased slightly,showing obvious defects and depressions.In IGFBP-4 control group,the synovial cells were tightly connected with fine spines,and the connected reticular structure was stable.The cartilage showed smooth and flat,and the number of chondrocytes was the highest in each group,with no obvious defects or cavities.6.Localization expression of IGFBP-4 in synovium:Immunohistochemical staining showed that the optical density of IGFBP-4 mice was higher than that of C57 mice,which proved that IGFBP-4 was highly expressed in synovium of IGFBP-4 transgenic mice.Compared with C57 control group,C57 OA group had deeper staining,obvious difference in AOD value and stronger immune response(P<0.05).Compared with IGFBP-4 control group,IGFBP-4 OA group has deeper staining,obvious difference in AOD value and stronger immune response(P<0.05),which has statistical significance;Compared with C57 group,IGFBP-4 group showed great difference in staining,showing dark brown and strong immune response(P<0.001).7.Synovial IGFBP-4 protein expression: As IGFBP-4 transgenic mice,the expression of IGF-BP-4 is over-expressed at the basic expression level,which is significantly different from C57 mice(P<0.001).Compared with C57 control group,the expression of IGFBP-4 in C57 OA group increased significantly(P<0.01).Compared with C57 control group,the expression of IGFBP-4 in C57 OA group increased significantly(P<0.01).Compared with IGFBP-4 control group,the protein expression level in IGFBP-4 OA group was significantly different(P<0.05).The expression of PENK protein: the expression of PENK protein in C57 OA group was significantly different from that in C57 control group(P<0.001).Compared with IGFBP-4OA group,the protein expression of C57 OA was significantly different(P<0.001).Compared with IGFBP-4 control group,IGFBP-4 OA group had different protein expression,(P<0.001),which was statistically significant.Conclusions IGFBP-4 is involved in the whole process of knee arthritis,and its secretion increases with the development of the disease IGFBP-4 inhibited the pain caused by knee osteoarthritis;IGFBP-4 plays an important role in the proliferation of chondrocytes.Figure13;Table2;Reference 141... |
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