Objective To evaluate the feasibil ity of intrauterine abdominal wall defect repair of fetal lamb at late pregnancy. Methods Eight healthy pregnant ewes at 110-115 days of gestation (weighing 14-22 kg) were randomly divided into 2 groups. In group A (n=3), the abdominal wall defect of 5 cm × 1 cm was made in the fetal lambs, then was closed by strengthening suture; in group B (n=5), the abdominal wall defect of 5 cm × 2 cm was made in the fetal lambs, then was repairedby 2 layers of biological patches. After the lambs del ivered naturally, the lambs and their wounds were observed; at 10th day after birth, the scars were harvested for biomechanical and histological observations. Results One ewe of group A and 2 ewes of group B aborted, while the others were successfully del ivered. In group A, the abdominal incisions of 2 lambs healed well with a l ine-l ike scar and mild intra-abdominal adhesion, and the scar thickness was 4-5 mm. In group B, the abdominal incisions of 3 lambs did not heal completely with minor intra-abdominal adhesions, and the scar thickness was 3-4 mm. The wound breaking strength was 16, 20 N in group A and 10, 14, and 18 N in group B, respectively. A sl ight scar was seen in group A; skin ulcer and underlying fibrous connective tissue with inflammatory cell infiltration were seen in group B. Conclusion It was feasible to repair the abdominal wall defect of fetal lamb at late pregnancy in uterine. Small abdominal wall defect can be sutured directly; biological patch can be used to repair larger abdominal wall defect.
Objective To explore the osteogenic potential of cervical intervertebral disc fibroblasts in vitro, to investigate the regulatory factors of recombinant human bone morphogenetic protein 2(rhBMP-2) and tumor necrosis factor α(TNF-α) on osteogenic phenotype of fibroblasts and to discuss the condition that facilitates osteogenesis of fibroblasts. Methods Theannulus fibroblasts cell lines of experiment goats were established in vitro and the biologicspecificity was found. According to different medias, 4 groups were included in this experiment: control group, TNF-α group ( 50 U/ml TNF-α), rhBMP-2 group (0.1 μg/ml rhBMP-2) and TNF-α+rhBMP-2 group (50 U/ml TNF-α+0.1 μg/ml rhBMP-2). Thefibroblasts were incubated in the media for about 3 weeks,and then the markers for osteogenic features were investigated by biochemistry, histochemistry observations. Results rhBMP-2 and TNF-α had no effect on the proliferation of fibroblasts from the experiment goats. rhBMP-2 or TNF-α could stimulate fibroblasts to secrete alkaline phosphatase and collagen type Ⅰ. The combined use of rhBMP-2 and TNF-α or the single use of rhBMP-2 could make fibroblasts to secrete osteocalin and the morphological changes of the fibroblasts were very obvious. Histochemical study of the nodules with specific new bone labeler(Alizarin red S) revealed positive reaction, denoting that the nodules produced by the fibroblasts werebone tissues. There was statistically significant difference(Plt;0.05) inALP activity between 3 experimental groups and control group and in secretion of osteocalcin between rhBMP-2 group, TNF-α+rhBMP-2 group and control group. Conclusion The results point out clearly that rhBMP-2 can induce theosteogenic potential of annulus fibroblasts in vitro.
Objective
To evaluate the influence of PKH26 labeling on the biological function of the goat nucleus pulposus cells and the biological function of seeded cells in nude mice by in vivo imaging techonology.
Methods
Primary nucleus pulposus cells were isolated by enzymatic digestion from the nucleus pulposus tissue of the 1-year-old goat disc. The nucleus pulposus cells at passage 1 were labeled with PKH26 and the fluorescent intensity was observed under the fluorescence microscopy. The labeled cells were stained with toluidine blue and collagen type II immunocytochemistry. The cells viability and proliferation characteristics were assessed by trypan blue staining and MTT assay, respectively. Real-time fluorescent quantitative PCR was used to detect the gene expressions of collagen types I and II, and aggrecan. The fluorescent intensity and scope of the nucleus pulposus cells-scaffold composite in vivo for 6 weeks after implanting into 5 6-week-old male nude mice were measured by in vivo imaging technology.
Results
Primary nucleus pulposus cells were ovoid in cell shape, showing cluster growth, and the cells at passage 1 showed chondrocyte-like morphology under the inverted phase contrast microscope. The results of toluidine blue and collagen type II immunocytochemistry staining for nucleus pulposus cells at passage 1 were positive. The fluorescent intensity was even after labeling, and the cell viability was more than 95% before and after PKH26 labeling. There was no significant difference in cell growth curve between before and after labeling (P gt; 0.05). The real-time fluorescent quantitative PCR showed that there was no significant difference in gene expressions of collagen types I and II, and aggrecan between before and after labeling (P gt; 0.05). Strong fluorescence in nucleus pulposus cells-scaffold composite was detected and by in vivo imaging technology.
Conclusion
The PKH26 labeling has no effect on the activity, proliferation, and cell phenotype gene expression of the nucleus pulposus cells. A combination of PKH26 labeling and in vivo imaging technology can track the biological behavior of the cells in vivo.
Objective
To establish a rapid, simple, and economic method to prepare osteoporosis (OP) in vitro model.
Methods
Eighty pairs of fresh goat femur were collected from 18-month-old female goats and were randomly divided into 4 groups (20 pairs in each group). The femur was immersed decalcifying solution (18% EDTA) for 1-5 days (group B), 6-10 days (group C), and 11-15 days (group D), while group A had no treatment as control. Four pairs of femur were taken out every day. Quantitative computed tomography was used to scan the medial and lateral femoral condyles, and the bone mineral density (BMD) was calculated. Electronic universal testing machine was used to do three-point bending test and compress and tensile ultimate strenght test, and the mechanical parameters for femur were calculated.
Results
With demineralized time passing, BMD of the medial and lateral femoral condyles were downtrend in groups A, B, C, and D, showing significant differences among 4 groups (P lt; 0.05); BMD of the lateral femoral condyle was significantly higher than that of the medial femoral condyle in each group (P lt; 0.05). The three-point bending test showed that broken load, ultimate strength, and elastic modulus of groups A and B were significantly higher than those of groups C and D (P lt; 0.05); but no significant difference was found between groups A and B, and between groups C and D (P gt; 0.05). Compress and tensile ultimate strength test showed that the compress and tensile ultimate strengths were significantly higher in group A than in groups C and D (P lt; 0.05), and in group B than in group D (P lt; 0.05), but no significant difference was found between groups A and B, between groups B and C, and between groups C and D (P gt; 0.05).
Conclusion
The 18% EDTA immersing for 6-15 days is a fast, simple, economical method to prepare an OP in vitro model of goat femur.
Objective
To evaluate the application of artificial lamina of multi-amino-acid copolymer (MAACP)/nano-hydroxyapatite (n-HA) in prevention of epidural adhesion and compression of scar tissue after posterior cervical laminectomy.
Methods
Fifteen 2-year-old male goats [weighing, (30 ± 2) kg] were randomly divided into experimental group (n=9) and control group (n=6). In the experimental group, C4 laminectomy was performed, followed by MAACP/n-HA artificial lamina implantations; in the control group, only C4 laminectomy was performed. At 4, 12, and 24 weeks after operation, 2, 2, and 5 goats in the experimental group and 2, 2, and 2 goats in the control group were selected for observation of wound infection, artificial laminar fragmentation and displacement, and its shape; Rydell’s degree of adhesion criteria was used to evaluate the adhesion degree between 2 groups. X-ray and CT images were observed; at 24 weeks after operation, CT scan was used to measure the spinal canal area and the sagittal diameter of C3, C4, and C5 vertebrea, 2 normal goats served as normal group; and MRI was used to assess adhesion and compression of scar tissue on the dura and the nerve root. Then goats were sacrificed and histological observation was carried out.
Results
After operation, the wound healed well; no toxicity or elimination reaction was observed. According to Rydell’s degree of adhesion criteria, adhesion in the experimental group was significantly slighter than that in the control group (Z=
—
2.52, P=0.00). X-ray and CT scan showed that no dislocation of artificial lamina occurred, new cervical bone formed in the defect, and bony spinal canal was rebuilt in the experimental group. Defects of C4 vertebral plate and spinous process were observed in the control group. At 24 weeks, the spinal canal area and sagittal diameter of C4 in the experimental group and normal group were significantly larger than those in the control group (P lt; 0.05), but no significant difference was found between experimental group and normal group (P gt; 0.05). MRI showed cerebrospinal fluid signal was unobstructed and no soft tissue projected into the spinal canal in the experimental group; scar tissue projected into the spinal canal and the dura were compressed by scar tissue in the control group. HE staining and Masson trichrome staining showed that artificial lamina had no obvious degradation with high integrity, some new bone formed at interface between the artificial material and bone in the experimental group; fibrous tissue grew into defect in the control group.
Conclusion
The MAACP/n-HA artificial lamina could maintaine good biomechanical properties for a long time in vivo and could effectively prevent the epidural scar from growing in the lamina defect area.
Objective To investigate the ability to repair goat tibia defect with marrow stromal stem cells (MSCs) and bio-derived bone, and the feasibility of the compounds as bone substitute material. Methods MSCs were cultured with the bioderived bone in vitro, and the 20 mm tibia defect of goat was made and fixedwith plate. Eighteen goats were divided into experimental group, control group and blankgroup. The defects were not filled with anything in blank group, with tissue engineering bone in experimental group and bio-derived bone in control group. Therepair capability was assessed by physical, X-ray and bone mineral density examinations8,12,16, and 24 weeks after operation. Results In experimental group, the defects were partially repaired 8 weeks, and completely repaired12 and 16 weeks; there was significant difference in bone density between experimental group and control group (P＜0.05) 8,12 and 16 weeks, but no significant difference 24 weeks. The defects of blank group were not repaired 24weeks. Conclusion The tissue engineering bone can efficiently repair bone defect, and its repair capability is better than that of bio-derived bone alone both in quantity and quality of boneformation.
Objective To study the method to prepare the animal model of goat cleft palate by injection of anabasine and the effect of the malformation on the development of the facial mid-part. Methods A total of 40 female boer hybrid goats were selected, aging 8-12 months and weighing 35-55 kg. The mating day was 0 day, and at 30 days the goats assured pregnant byB type ultrasonic test were divided into 4 groups (n=10) according to intramuscular injection of 10 (experimental group 1), 15 (experimental group 2), 20 (experimental group 3) mg/ d, and no injection (control group), respectively, from the 31st to 42nd day. At pregnant 120 days and 1 month after birth, 5 fetal goats of each group were used for three dimensional reconstruction ofskull with CT scan. The maxillary bone width named as PPMM and the maxillary bone length named as APMM were measured then the hard palate general observation was performed and dry skull of goats was harvested to observe the development of maxillary. Results After injection, all pregnant lambs aborted in experimental group 3; 2 pregnant lambs aborted and 8lambs maintained pregnancy in experimental group 2. At 120 days of pregnant, no cleft palate was observed in 5 fetal lambs of experimental group 1 and control group, respectively; cleft palate and maxillary dysplasia occurred in 3 fetal lambs of experimental group 2. Among 11 newborn lambs of experimental group 1 and 8 newborn lambs of control group, no cleft palate was observed;among 7 newborn lambs of experimental group 2, cleft palate occurred in 5 with obvious maxillary dysplasia and eating difficultly. General observation of hard palate and dry skull showed obvious hypoplasia of maxillary in experimental group 2. There were significant differences in PPMM and APMM between the experimental group 2 and the control group at pregnant 120 days and 1 month after birth (P lt; 0.05). Five lambs with cleft palates of experimental group 2 survived for 1-2 months. Conclusion The animal models of goat cleft palate can established by intramuscular injection of anabasine at a dose of 15 mg/d from the 31st to 42nd day of pregnant. The facial character of the induced cleft palate goat is similar to that of human cleft palate.
ObjectiveTo discuss the effect of three different ways of annulus fibrosus incision on the biomechanical strength of intervertebral disc.
MethodsA total of 30 goats underwent intervertebral disc nucleus pulposus extraction at L3, 4 and L4, 5 by the working channel in group A (n=10), by circular incision in group B (n=10), and by square incision in group C (n=10). The body weight, male and female ratio, age, intraoperative blood loss, and wound healing time were recorded and compared among 3 groups. The survival rate and wound healing situation were observed after operation. At 24 weeks after operation, the goats were sacrificed, MRI images were taken to observe the signal intensity of nucleus pulposus. The disc height of L3, 4 and L4, 5 was measured to calculate the loss of disc height; biomechanical test was used to assess the strength of the disc and anulus. Histological staining was also conducted to observe the repair effect at L4, 5.
ResultsThere was no significant difference in body weight, male to female ratio, age, intraoperative blood loss, and wound healing time among groups (P>0.05). All goats survived to the end of the experiment. MRI examination showed decreased signal intensity in 3 groups, indicating intervertebral disc degeneration. According to modified Thompson classification method, the degree of intervertebral disc degeneration of group A was significantly higher than that of groups B and C (P<0.05), but no significant difference was found between groups B and C (P>0.05). Difference was not significant in intervertebral space height before operation among 3 groups (P>0.05). But after 24 weeks, the intervertebral space height in group A was significantly higher than that in groups B and C (P<0.05), and the intervertebral space height loss in group A was significantly lower than that in groups B and C (P<0.05). The biomechanical strength in group A was also significantly higher than that in groups B and C (P<0.05), but no significant difference was found between group B and group C (P>0.05). HE and Masson staining showed good continuity of annulus fibrosus and clear layers in group A; poor continuity of annulus fibrosus and obvious scar tissues were observed in groups B and C.
ConclusionApplication of working channel may have less destruction of annulus fibrosus, it plays a positive role in the maintenance of biomechanical strength and repair of annulus fibrosus.
Objective To study the vascularization of the compositeof bio-derived bone and marrow stromal stem cells(MSCs) in repairing goat tibial shaft defect.Methods Bio-derived bone was processed as scaffold material. MSCs were harvested and cultured in vitro. The multiplied and induced cells were seeded onto the scaffold to construct tissue engineered bone. A 20 mm segmental bone defect inlength was made in the middle of the tibia shaft in 20 mature goats and fixed with plate. The right tibia defect was repaired by tissue engineered bone (experimental side), and the left one was repaired by scaffold material (control side).The vascularization and osteogenesis of the implants were evaluated by transparent thick slide, image analysis of the vessels, and histology with Chinese ink perfusion 2, 4, 6, and 8 weeks after operation.Results More new vessels were found in control side than in experimental side 2 and 4 weeks after implantation (Plt;0.05). After 8 weeks, there was no significant difference in number of vessels between two sides(Pgt;0.05), and the implants were vascularized completely. New bone tissue was formed gradually as the time and the scaffold material degraded quickly after 6 and 8 weeks in the experimental side. However, no new bone tissue was formed andthe scaffold degraded slowly in control side 8 weeks after operation.Conclusion Bio-derived bone has good quality of vascularization. The ability of tissue-engineered bone to repair bone defect is better than that of bio-derived bone alone.
