OBJECTIVETo investgate the expression patterns of bone morphogenetic protein-2 (BMP-2) in the distraction area following plRES-hBMP2-VEGFI65 gene transfection at different time during mandibular distraction osteogenesis in a rabbit model.

METHODS48 New-Zeland rabbits were employed to underwent osteotomy and distraction devices implantation on mandible bilaterly. After 3 days of latency period, the devices were activated at the rate of 0. 8 mm per day for 10 days. The rabbits were randomly divided into 4 groups (group A, B, C and D). Group A, B and C were transfected recombinant plasmids pIRES-hBMP2-hVEGF165 via electroporation-mediated approach at latency period, distraction period, consolidation period respectively. Group D was used as control group without gene transfection. Three rabbits in each group were sacrificed at 1, 2, 4 weeks of consolidation respectively. The mandibles were harvested for immunohistochemical staining detection of BMP-2 expression respectively, which were analyzed by CMIAS series multifunction color quantitative analysis of pathological image analysis system.

RESULTSBMP-2 expression was found to be mainly located in the monocyte, fibroblast of the granulation tissue, the osteoblasts, osteocyte on the surface of new formed trabecular, and the connective tissues surrounding the new formed bone. The expression in group B was superior to other groups. Image analysis showed that, at the first week and second week of consolidation, the expression abosordbance A in group B (0. 58 ± 0. 03 and 0. 34 ± 0. 02) was relatively higher, when compared with that in group A (0. 42 ± 0. 02 and. 31 ±0.01), C(0.32 ±0.01 and 0.30 ±0.01)and D(0.27 ±0.01 and 0.23 ±0.02), showing a significant difference(P <0. 05). It was also relatively higher in group A(0. 42 ± 0. 02 and 0. 31 ± 0. 01) and C(0. 32 ± 0.01 and 0.30 ± 0.01), when compared with that in group D(0. 27 ±0.01 and 0.23 ± 0. 02), showing a significant difference( P < 0. 05) , but there was no significant difference ( P > 0. 05) between group A and group C. At the fourth week of consolidation, the expression decreased and there was no significant difference among group A, B, C, D.

CONCLUSIONSThe electroporation-mediated gene transfection which is transfected at the beginning of traction can promote BMP-2 expression effectively, stimulate bone marrix synthesis and induce proliferation and differentiation of fibroblasts, osteoblasts, endothelial cells, which further effectively promote the new bone formation. It suggests that the distraction stage is the optimal time for gene therapy.

Animals ; Bone Morphogenetic Protein 2 ; metabolism ; Electroporation ; methods ; Genetic Therapy ; methods ; Mandible ; surgery ; Osteogenesis ; Osteogenesis, Distraction ; Osteotomy ; Rabbits ; Time Factors ; Transfection ; methods

Objective To investigate the effect of hyperbaric-oxygen therapy on osteoprotegerin (OPG) and integrin β1 (Itgβ1 ) expression during mandibular distraction osteogenesis .Methods Forty New-Zealand rabbits were used .The animals were randomly divided into two groups (experimental group and control group) with 20 animals each ;after accomplished osteotomy and implant distraction devices on mandible bilaterally for 3 days of latency period ,the device was activated at the rate of 0 .8 mm per day for 10 days .All animals in the experimental group were subjected to hyperbaric oxy -gen for 90 minutes once a day since the beginning of distraction ,and lasted for four weeks .In control group ,all the distractors were activated following the same distraction protocol as the experimental group ,but without hyperbaric oxygen therapy .Five animals of each group were sacrificed at 10th day after distraction ,7th ,14th and 28th day of consolidation , respectively .The lengthened mandibles were harvested and processed for immunohistochemical examinations to detect OPG and Itg β1 expres-sion in the distraction gap .Semi-quantitative analysis was carried out by image analysis software . Results OPG staining was mainly located in the membrane and cytoplasm of osteoprogenitor cells and osteoblasts in the distraction zones .The expression of OPG increased after distraction accomplished and reached to the peak at 7th day of consolidation ,and then decreased gradually .At every time point , the level of expression of OPG in the experimental group was remarkably higher than those in control group .There were significant differences between the experimental group and control group ( P <0 .01) .Itgβ1 mainly located in actively proliferating osteoblasts ,fibroblasts and mesenchymal cells . The expression of Itgβ1 decreased significantly after reached to the peak at the 10th day distraction .At 10th day distraction ,7th and 14th day of consolidation ,Itgβ1 expressed more strongly than that in the experimental group ,which was remarkably higher than those in control group .There were significant differences between experimental group and control group (P < 0 .05) .At 28th day of consolidation , Itgβ1 expressed weakly ; there was no significant difference between the two groups ( P > 0 .05 ) . Conclusions Hyperbaric oxygen therapy can up-regulate the expression of OPG and Itgβ1 in the dis-traction gap ,which may promote osteoblast differentiation ,proliferation ,enhance osteoblast func-tion ,and new bone formation in distraction gap .

Objective:To investigate the effect of mandibular angle osteotomy on the morphological changes of mandible by using cone beam computed tomography (CBCT) scanning data and three-dimensional cephalometry.Methods:According to included and excluded criteria, the complete CBCT data of 20 female patients (aged 20-35 years with an average age of 25.5 years) from January 2016 to June 2018 who underwent curved mandibular angle osteotomy combined with splitting cortiectomy were selected. Seven items reflecting mandibular morphology before and after surgery were measured respectively. All the data were analyzed by the means of SPSS 12.0; linear correlation analysis and paired t test were used to evaluate the change of andibular morphology.Results:The measurement results of the mandible pre- and post-operative 10 days showed as follows: Go-Go decreased, both sides of Cd-Go, Go-Ri and MR-MA decreased, both sides of Go-Me became longer, both sides of Ar-Go-Me and MP-FH increased. The paired t-test results showed that there was significant difference before and after operation ( P<0.05), but there was no significant difference between the left and right measurement items ( P>0.05). Compared with that in 10 days after operation, the measurement items also changed 6 months after operation. There was no statistical difference between the above measurement items 6 months after surgery and 10 days after surgery ( P>0.05), and no statistical difference between the left and right sides ( P>0.05). Conclusions:The mandibular three-dimensional model which is reconstructed based on CBCT data, not only displays the three-dimensional anatomical structure that cannot be presented on X-ray film visually and comprehensively by means zoom, rotation and other operations, but also precisely and accurately shows the change of the shape of the mandible from the sagittal, coronal and horizontal plane with arbitrary cutting and rotation. The measurement of mandible is more accurate and reliable, and the surgical plan of mandibular angle osteotomy can be accurately planned preoperatively, and the operative effect can be quantitatively evaluated postoperatively.

Objective:To seek a minimally invasive method for costal cartilage harvest by using two different costal cartilage harvest techniques in rhinoplasty and to compare their influence on donor site pain.Methods:Fourty-three female patients who underwent costal cartilage harvest for rhinoplasty from Dec. 2016 to Dec. 2017 were randomly divided into two groups. We harvested the right side seventh costal cartilage in both groups. In control group, we harvested a full thickness segment of costal cartilage in each patient, whereas we harvested a split thickness segment of costal cartilage by preserving the superior strip in experimental group. Donor site pain was evaluated via visual analogue scale (VAS) 6 h, 24 h, 48 h and 72 h after surgery.Results:The VAS scores (mean±standard deviation) at different time points in the control group were (5.515±1.085), (5.250±1.302), (5.315±1.117) and (4.895±1.042). And in the experimental group, they were (2.665±0.713), (2.261±0.642), (1.609±0.398) and (1.383±0.514), respectively. The VAS scores at different time points were significantly higher in the control group than that in the experimental group ( P<0.05). Conclusions:The superior strip preserved costal cartilage harvest technique significantly reduces postoperative donor site pain.

Objective:To investigate the effect of eyebrow arch augmentation with personalized polyether ether ketone (PEEK) implant assisted by endoscope.Methods:From January 2019 to August 2021, 9 patients with low and flat eyebrow arch requiring eyebrow arch augmentation were treated in the plastic surgery department of the Friendship Plastic Surgery Hospital Affiliated to Nanjing Medical University. The cranial and maxillofacial CT scanning data were obtained before operation, the eyebrow arch elevation range and height were designed according to the patient's requirements, and personalized peek implants were manufactured. During the operation, a small temporal hairline incision was used to accurately separate the implantation cavity of individualized peek implants under the periosteum of the eyebrow arch implantation area with the aid of endoscope. Personalized PEEK implants were implanted under endoscope to make them fully fit with the eyebrow arch bone and fixed with titanium nails. Photos were taken and analyzed before and after operation.Results:All patients were followed up for 3 months to 2 years. Their facial expressions were normal, and there were no motor nerve injury, rejection and iatrogenic infection. The patients were satisfied with the postoperative effect. Compared with before operation, the low level of orbital bone in eyebrow area was improved, and the facial contour was three-dimensional and harmonious.Conclusions:The eyebrow arch augmentation with individualized peek implant assisted by endoscope is safe and effective. It can greatly reshape the upper contour of the face, deepen the upper eyelid fossa and improve the convex eye phenomenon, so as to achieve the cosmetic effect of enhancing the three-dimensional sense of the eyebrow orbital area, which is worthy of clinical application.

Objective:To investigate the clinical effect of W-shaped genioplasty in the correction of broad and short chin deformity.Methods:Thirty-eight patients (5 males, 33 females, aged 20 to 41 years, mean 27.3 years) complained with broad and short chin were admitted to the Affiliated Friendship Plastic Surgery Hospitalof Nanjing Medical University from January 2019 to December 2021. CBCT scan and three-dimensional reconstruction were performed to design osteotomy line and determine the distance of chin lengthening, narrowing and advancing or retrocession preoperatively. Under general anesthesia, the W-shaped osteotomy was performed using an intraoral incision, and the angle between the bilateral free bone fragments, the distance of downward and forward movement were adjusted to change the curvature, width, length and prominence of the lower edge of the chin according to the preoperative designs. The results were evaluated by clinical appearances and image analyses at a follow-up of 3-24 months.Results:The amount of vertical lengthening of the chin in 38 cases were 2 mm to 5 mm, with an average of 3.02 mm. The horizontal narrowing width distances were 3-7 mm, with an average of 5.6 mm. The patients were followed up for 3-24 months, with an average of 10.6 months. There were no complications such as hematoma, wound dehiscence, accidental fracture, surgical area infection and permanent neurosensory disorder. 38 patients had transient sensory loss in the lower lip region of varying degrees, but all recovered spontaneously during routine follow-up period. All patients were satisfied with the improvement of facial contour.Conclusions:W-shaped geinoplasty preserves the central bone of the chin and the attachment of genioglossus muscle, which does not affect the normal anatomy and physiological function of the oral cavity. After osteotomy, the bone is removed and the bilateral bone fragments move flexibly. It can effectively change the radian, width, length and protrusion of the lower edge of the chin in three dimensions, so as to correct the wide and short deformity of the chin.

Objective:To investigate the clinical outcomes of personalized polyetheretherketone (PEEK) implant in the correction of nasolabial fold depression.Methods:A total of 30 patients with nasolabial fold depression (5 males, 25 females, aged 26 to 52 years, mean 36.3 years) admitted to the Affiliated Friendship Plastic Hospital of Nanjing Medical University who want to undergo nasolabial fold augmentation from January 2019 to January 2021. All patients underwent CBCT scan and three-dimensional simulation, the personalized PEEK implant was designed and produced with CAD/CAM technique, the personalized PEEK was implanted during the operation. The patients were followed up for 3-12 months, and the wrinkle score and satisfaction were compared before operation and 3 months and 6 months after operation.Results:The depressions of nasolabial fold were significantly improved in all patients, and there were no complications such as hematoma and infection after operation. During the follow-up, there was no implant displacement or exposure, and the effect was stable and lasting. The scores of wrinkles at 3 months after operation (2.30±0.47) and 6 months after operation (2.17±0.38) were significantly lower than those before operation (4.03±0.67), and the scores of satisfaction were significantly higher than those before operation ( P<0.05). The scores of satisfaction at 3 months after operation (3.97±0.56) and 6 months after operation (4.23±0.57) were significantly higher than those before operation (1.70±0.60). The difference was statistically significant ( P<0.05). Conclusions:3D printing personalized PEEK prosthesis is effective in correcting nasolabial fold depression, and it is safe and stable, so it is recommended for clinical application.

Objective:To investigate the effect of electroporation-mediated local gene therapy on the expression of Wnt3a and β-catenin in callus of distraction gap during mandibular distraction osteogenesis of rabbits.Methods:The experiments were conducted in the laboratory of the Affiliated Friendship Plastic Surgery Hospital of Nanjing Medical University from September 2019 to December 2019. Forty eight New-Zealand rabbits were randomly divided into control group (group A), gene therapy group (group B) and normal saline group (group C), with 16 rabbits in each group. After bilateral mandible osteotomy and distractors were implanted, the distractors were activated at a speed of 0.8 mm/d on 4th day, postoperatively, and lasted for 7 days, followed by consolidation period. Group A distracted only, group B was subject to local injection of recombinant plasmid pIRES-hBMP2-hVEGF165 in the distraction gap and electroporation stimulation at the beginning of activation distractors; and group C local injection of the same dose of normal saline in the distraction gap and electroporation stimulation at the beginning of activation distractors. Four animals in each group were sacrificed on the day at the end of distraction, 7th, 14th, 28th days of consolidation period, respectively. The callus in the distraction gap was taken for immunohistochemical staining and RT-PCR to detect the expression of Wnt3a and β-catenin, and image analysis was performed. SPSS 22.0 statistical software was used for data analysis.Results:Immunohistochemical staining showed that Wnt3a and β-catenin were mainly located in the cytoplasm and nuclei of fibroblasts, chondrocytes and osteoblasts in callus tissue. Immunohistochemistry and RT-PCR showed that the expression of Wnt3a and β-catenin reached a peak at the end of distraction. With the disappearance of distraction tension, the expression of Wnt3a and β-catenin gradually decreased. After gene therapy intervention, the expression of Wnt3a and β-catenin was significantly increased, and the expression of Wnt3a and β-catenin in group B was the highest at each time point, with statistically significant difference compared with groups A and C ( F=96.3, P<0.01). Conclusions:Gene therapy promotes the expression of Wnt3a and β-catenin in the callus of distraction gap, regulating the balance of the bone reconstruction system and thus promoting the formation of new bone in the distraction gap.

Objective: To explore the role of β-catenin in distraction osteogenesis of new bone formation, the expression of β-catenin in the distraction gap callus was detected during rabbit mandibular distraction osteogenesis. Methods: 26 New-Zealand rabbits were randomly divided into 3 groups. Group A is a normal control group with 2 rabbits, group B is the mandibular defect control group, and group C is the distraction group. Group B and C with 12 rabbits, respectively. The two rabbits in group A without surgery, their mandibles are normal control. In group B, vertical osteotomy was performed between the first molar and the mental foramen on the mandibles bilaterally, followed by rigid internal fixation with titanium plates and screw with 5 mm gap immediately. In group C, after the same osteotomy was performed, the fragments of mandibles were reduced and fixed with mandibular distractors bilaterally. On the fourth day postoperatively, the distraction started at a rate of 0.8 mm/d and lasted for 7 days, followed by consolidation period. Two rabbits of group B and C were sacrificed at 6th, 10th, 17th, 24th, 31st, 38th day postoperatively, respectively. The newly formed callus in the distraction gap of mandibles was harvested for Western blotting and immunohistochemistry examination to detect the distribution and expression of β-catenin. The experimental data were analyzed by SPSS 22.0 statistical software using Spearman function. Results: The result of Western blotting showed that the expression of β-catenin gradually increased at distraction period(6-10 days after surgery) and reached the peak at the end of the distraction period(10th day postoperatively), it gradually decreased during the consolidation period. However, the expression of β-catenin in group C was higher than that of group B. Immunohistochemistry stain showed that the expression of β-catenin mainly located in inflammatory cells(eg. monocyte), fibroblast of the granulation tissue, the osteoblasts, osteocyte on the surface of new formed trabecular, and the connective tissues surrounding the new bone in the new formed callus. Cytoplasmic and nuclear staining were positive. In group C, the expression of β-catenin was strong (3.245 8±0.132 3) after distraction (6th day postoperatively), and reached a peak (4.602 8±0.021 9) on the 10th day postoperatively. With the disappearance of the distraction stress, the expression of β-catenin gradually decreased since17th day postoperatively(3.639 8±0.125 5), but the staining was still positive. In group B, the strong positive staining of β-catenin on the 6th day after surgery (2.734 0±0.134 7), the strongest staining on the 10th day after surgery (3.101 3±0.104 8), and the expression of β-catenin on the 17th day after surgery (2.542 8±0.211 1) was weaker than that on the 10th day after surgery. At each time point, the expression of β-catenin in group C was significantly higher than that in group B, and the difference was statistically significant (r=0.943, P=0.005 6). Conclusions During mandibular distraction osteogenesis, the distraction stress activates the Wnt signal pathway to enhance the expression of β-catenin, it suggests that β-catenin plays an important role in the transformation of the mechanical signal to chemical signals during the process of distraction osteogenesis, and participates in the regulation of new bone formation during distraction osteogenesis.