Objective To investigate the distribution of plantar pressures and bone stresses of the foot with high,normal and low arch morphologies,and reveal the influence of arch morphology on foot biomechanical properties.Methods A total of 127 young females were recruited.The foot type was classified by collecting the morphological data of the foot with the three-dimensional(3D)foot scanner,and three types of the foot arch morphology were selected for analysis.The geometric model of foot bone was obtained by CT scanning,so as to establish the biomechanical finite element model of the foot.A load of 50％human body weight was applied to the model to simulate the state of bipedal standing.Results The calculated plantar contact area was compared with the measured results,and the relative error values were smaller than 10％,which proved the validity of the finite element model.The peak plantar pressure under three types of arch morphologies was located in the hind foot region,and the heel pressure of high-and low-arched foot was higher than that of normal-arched foot.Compared with normal-arched foot,high-arched foot showed a significant increase in stress in the hind foot area,the peak stress of soft tissues was 299.45％higher,and the peak bone stress was 93.19％higher.For low-arched foot,the plantar contact area increased by 13.28％and calcaneal stress increased by 98.09％.The peak bone stresses of high-,normal-and low-arched foot were located at the talus,which were 9.903,19.921 and 36.308 MPa,respectively.Conclusions This study supports the association between abnormal arch morphology,foot pain and foot diseases,and provides a basis and direction for the design of orthopedic insoles and arch support structures for abnormal feet.

Objective To investigate the distribution of plantar pressures and bone stresses of the foot with high,normal and low arch morphologies,and reveal the influence of arch morphology on foot biomechanical properties.Methods A total of 127 young females were recruited.The foot type was classified by collecting the morphological data of the foot with the three-dimensional(3D)foot scanner,and three types of the foot arch morphology were selected for analysis.The geometric model of foot bone was obtained by CT scanning,so as to establish the biomechanical finite element model of the foot.A load of 50％human body weight was applied to the model to simulate the state of bipedal standing.Results The calculated plantar contact area was compared with the measured results,and the relative error values were smaller than 10％,which proved the validity of the finite element model.The peak plantar pressure under three types of arch morphologies was located in the hind foot region,and the heel pressure of high-and low-arched foot was higher than that of normal-arched foot.Compared with normal-arched foot,high-arched foot showed a significant increase in stress in the hind foot area,the peak stress of soft tissues was 299.45％higher,and the peak bone stress was 93.19％higher.For low-arched foot,the plantar contact area increased by 13.28％and calcaneal stress increased by 98.09％.The peak bone stresses of high-,normal-and low-arched foot were located at the talus,which were 9.903,19.921 and 36.308 MPa,respectively.Conclusions This study supports the association between abnormal arch morphology,foot pain and foot diseases,and provides a basis and direction for the design of orthopedic insoles and arch support structures for abnormal feet.

Objective To investigate the revascular and transplanted effects of islet grafts after co-transplantation with vascular endothelial cells ( ECs) in diabetic rats. Methods The rat ECs and islet cells were isolated and purified, then subcutaneously co-transplanted to the inbred SD male rats with diabetes mellitus, the group of islets transplanted alone, group of phosphate buffered solution, and group of normal rats served as control. Islet grafts revascularization degree, islet cells activity and apoptosis were observed by immunohistochemical double staining of CD31, insulin and factor associated suicide (Fas) antibody. The results of intraperitoneal glucose tolerance test (IPGTT) and intraperitoneal insulin tolerance test (IPITT), the blood glucose and insulin levels of the rats and the survival time of the islet grafts were compared. Results The blood glucose concentrations of IPGTT and IPITT, the blood glucose and insulin levels of rats analyzed by multivariate analysis in the ECs and islets transplantation group were better than those in the islets transplantation alone group (P<0.05). The islet grafts mean survival time of the ECs and islets transplantation group was longer than that of the islets transplantation alone group (P<0.05). On the 7th day after transplantation, mean microvascular density of islet grafts per square millimeter in the ECs and islets transplantation group was 26.4 ± 6.1, significantly greater than that in the islets transplantation alone group 18.3 ± 5.7 (P<0.05). In the ECs and islets transplantation group, insulin staining intensity was higher than that in the islets transplantation alone group (P<0.05), while factor associated suicide(Fas) staining intensity was lower than that in the islets transplantation alone group ( P<0. 05 ). Conclusion Co-transplantation with ECs could promote the revascularization of islet grafts and improve the effect of islet transplantation.

Objective To investigate the influence of VEGF165 gene transfection on the revascularization and transplantation effect of islet grafts.Methods The rat islet cells were transfected with lentivirus containing VEGF165 gene (LV-VEGF165) in vitro,then transplanted to the renal capsule of inbred SD male rats with diabetes mellitus.Islet cells transfected with lentivirus marked with AcGFP1 and no VEGF165 gene were set as null vector control group (LV-AcGFP1 group),individual islet cells as blank control group.VEGF165 expression in vivo and in vitro was detected by ELISA.The islet grafts revascularization degree and islet cell activity were observed by immunohistochemical double staining of insulin and CD31 antibody.Blood glucose and insulin level of rats with diabetes mellitus and survival time of islet grafts were compared.Results The VEGF165 concentrations in the LV-VEGF165 group secreted by islet cells in vivo and in vitro were significantly higher than those in the LV-AcGFP1 group and the blank control group (P＜0.01).Mean microvascular density (MVD) of islet grafts per square millimeter in the LV-VEGF165 group was (24.3 ± 3.7),significantly greater than that in the LV-AcGFP1 group (12.4 ± 2.5) and the blank control group (12.4 ± 2.5) (P＜ 0.01).Insulin staining intensity in the LV-VEGF165 group was also higher than that in the LVAcGFP1 group and the blank control group.The blood glucose and insulin levels in rats with diabetes mellitus analyzed by multivariate analysis in the LV-VEGF165 group were controlled more effectively than those in the LV-AcGFP1 group and the blank control group (P＜0.01).The islet grafts mean survival time (MST) after transplantation in the LV-VEGF165 group was longer than that of the LVAcGFP1 group and the blank control group (P＜0).01).Conclusion The VEGF165 gene transfection to islet cells could promote the revascularization of islet grafts and improve the effect of islet transplantation.