ObjectiveTo construct bone morphogenetic protein 2 (BMP-2) gelatin/chitosan hydrogel sustained-release system, co-implant with induced pluripotent stem cells (iPS) derived mesenchymal stem cells (MSCs) to hydroxyapatite (HA)/zirconium dioxide (ZrO2) bio porous ceramic foam, co-culture in vitro, and to explore the effect of sustained-release system on osteogenic differentiation of iPS-MSCs.MethodsBMP-2 gelatin/chitosan hydrogel microspheres were prepared by water-in-oil solution. Drug encapsulation efficiency, drug loading, and in vitro sustained release rate of the microspheres were tested. HA/ZrO2 bio porous ceramic foam composite iPS-MSCs and BMP-2 gelatin/chitosan hydrogel sustained release system co-culture system was established as experimental group, and cell scaffold complex without BMP-2 composite gelatin/chitosan hydrogel sustained release system as control group. After 3, 7, 10, and 14 days of co-culture in the two groups, ALP secretion of cells was detected; gene expression levels of core binding factor alpha 1 (Cbfa1), collagen type Ⅰ, and Osterix (OSX) were detected by RT-PCR; the expression of collagen type Ⅰ was observed by immunohistochemical staining at 14 days of culture; and cell creep and adhesion were observed by scanning electron microscopy.ResultsBMP-2 gelatin/chitosan hydrogel sustained-release system had better drug encapsulation efficiency and drug loading, and could prolong the activity time of BMP-2. The secretion of ALP and the relative expression of Cbfa1, collagen type Ⅰ, and OSX genes in the experimental group were significantly higher than those in the control group at different time points in the in vitro co-culture system (P<0.05). Immunohistochemical staining showed that the amount of fluorescence in the experimental group was significantly more than that in the control group, i.e. the expression level of collagen type Ⅰ was higher than that in the control group. The cells could be more evenly distributed on the materials, and the cell morphology was good. Scanning electron microscopy showed that the sustained-release system could adhere to cells well.ConclusioniPS-MSCs have the ability of osteogenic differentiation, which is significantly enhanced by BMP-2 gelatin/chitosan hydrogel sustained-release system. The combination of iPS-MSCs and sustained-release system can adhere to the materials well, and the cell activity is better.
Objective By comparing with traditional L-shaped plate, to explore the effectiveness of new Pilon plate in the treatment of type C Pilon fracture.Methods A clinical data of 57 patients with type C Pilon fractures who met the selection criteria between May 2018 and January 2020 was analyzed retrospectively. Thirty-two patients were treated with new Pilon plate (trial group) and 25 patients with traditional L-shaped plate (control group). There was no significant difference in gender, age, cause of injury, fracture side and type, the interval between injury and operation between the two groups (P>0.05). The operation time and complications of the two groups were recorded. X-ray films were taken after operation to assess the quality of fracture reduction according to the Burwell-Charnley classification and fracture healing. Ankle function was evaluated according to Johner-Wruhs scoring standard and American Orthopaedic Foot and Ankle Society (AOFAS) score.Results The operations of the two groups were completed successfully, and the operation time of the trial group was significantly shorter than that of the control group (t=–3.025, P=0.005). After operation, the incision necrosis occurred in 2 cases of the control group, and the incisions of other patients in both groups healed by first intention. All patients were followed up 8-16 months, with an average of 10.1 months. There was no significant difference in follow-up time between the two groups (t=0.433, P=0.667). X-ray films showed that the ankle reduction of the trial group was rated as excellent in 28 cases and good in 4 cases, with an excellent and good rate of 100%, while in the control group, the ankle reduction was rated as excellent in 15 cases, good in 5 cases, and fair in 5 cases, with an excellent and good rate of 80.0%. There was a significant difference in the excellent and good rate of fracture reduction between the two groups (Z=–2.565, P=0.010). The fracture healed in both groups, and the healing time was (16.59±3.78) weeks in the trial group and (17.80±3.81) weeks in the control group, and there was no significant difference between the two groups (t=–1.191, P=0.239). At last follow-up, according to Johner-Wruhs scoring standard, the ankle joint function in the trial group was evaluated as excellent in 25 cases and good in 7 cases, with an excellent and good rate of 100%; the AOFAS score was 90.9±4.5. In the control group, 16 cases were excellent, 5 cases were good, and 4 cases were fair, and the excellent and good rate was 84.0%; the AOFAS score was 85.2±10.0. The ankle function scores of the trial group was superior to that of the control group (P<0.05). During follow-up, except for 1 case of ankle traumatic arthritis in the control group, there was no complication such as ankle malunion, plate loosening and fracture, or fracture reduction loss in both groups.Conclusion Compared with the traditional L-shaped plate, the new Pilon plate in the treatment of type C Pilon fracture has the advantages of high reduction quality, reliable fixation, less irritation to soft tissue, high fracture healing rate, and satisfactory functional recovery of ankle joint.