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BACKGROUND: Tissue-engineered bone has become an important means of repairing maxillofacial bone defects due to its minimally invasive, safe and accurate characteristics. OBJECTIVE: The model of chick chorioallantoic membrane was loaded with different intensities of electric field, to detect the blood vessel growth-related parameters, and to explore the effect of electric field on force-vascularization of tissue-engineered bone, in order to search for a method that can promote force-vascularization of tissue-engineered bone, thus increasing the repair success rate. METHODS: The model of chick chorioallantoic membrane (Inshell model) was established using the chicken embryos hatched for 8 days. The models were randomized into A, B, C, D, and E groups, followed by loaded with 0, -0.75, -1.5, -3 and +1.5 V and steady direct current electric fields at different directions. The images were taken at 0, 12, 24, 36 and 48 hours. The average blood vessel length and growth angle were measured by Image J, and analyzed on SPSS 22.0 software. RESULTS AND CONCLUSION: After loaded with different currents of electric fields, the average growth rate of vessel length in the groups A, B and C was 0.012, 0.023, and 0.047 5 mm/h, respectively. Independent sample t test results revealed that after loaded with -1.5 and 0 V for 48 hours, the average length of blood vessel was (4.22 ±0.436) and (3.21±0.31) mm/mm2, respectively, and the difference was significant (P < 0.01). After loaded with -1.5 and 0 V for 48 hours, the angle of blood vessels was (21.36±20.16)° and (82.17±50.44)°, respectively, and the difference was significant (P < 0.05). The chick chorioallantoic membrane around the electrode in the groups D and E degenerated and chick embryos died. These findings indicate that appropriate negative electricity promotes the growth of blood vessels, and changes the angle of blood vessel growth, suggesting that steady direct current electric field greatly affects chick chorioallantoic membrane. [ABSTRACT FROM AUTHOR]

BACKGROUND: Radiotherapy is one of the main methods for the treatment of brain tumors, which significantly improves the clinical efficacy. However, its side effects on normal brain tissue seriously affect the quality of life of patients. Therefore, it is particularly important to find a way to effectively prevent the damage of normal brain tissue and to study its mechanism. OBJECTIVE: To explore the effect and mechanism of Laminaria japonica polysaccharide intervention on radiation-induced brain injury in mice. METHODS: Ninety-six male Kunming mice, SPF grade, were randomly divided into four groups (n=24 per group): a control group, an irradiation group, a Laminaria japonica polysaccharide (LJP) group, and an irradiation+LJP group. All mice were given 7-day continuous administration before radiation, and then 60Go γ-rays (30 Gy) were used to establish a radiation brain injury model in mice. Immunofluorescence method was used to detect the expression of fibrinogen and activation and deposition of astrocytes in the brain tissue. The ultrastructural changes of the cerebrovascular system were investigated under transmission electron microscope. The motion trails of the mice in the Morris water maze were observed before and after treatment. RESULTS AND CONCLUSION: After radiotherapy, the expression of fibrinogen in brain tissue was significantly increased, and astrocytes were obviously activated, while the radiation plus LJP intervention significantly relieved the deposition of fibrinogen in mice. Under the electron microscope, the brain vascular endothelial cells swelled, the basement membrane was broken and shed, and the blood-brain barrier structure changed after radiation. However, the ultrastructural morphology of the mouse blood-brain barrier in the radiation+LJP group was similar to that of the control group. After radiation, the number of times and activity time of the mice passing through the platform area was significantly reduced in the Morris water maze test (P < 0.05), while the activities of the radiation mice in the platform area showed an increasing trend after the LJP intervention. These results suggest that the protective effect of LJP on radiation-induced brain injury may be mainly achieved by maintaining the stability of the blood-brain barrier structure and regulating its permeability. [ABSTRACT FROM AUTHOR]

BACKGROUND: Using the rapid growth period of the chorioallantoic membrane from the 8th day to the 12th day, vascular growth at bone defect end and vascular implantation of a bone graft substitute into the human body can be simulated. OBJECTIVE: To load hydroxyapatite into a chick embryo chorioallantoic membrane model, and to establish an implanted revascularization model. METHODS: Twelve rosette eggs were incubated under the same suitable conditions for 8 days. After windowing, the eggs were randomly divided into two groups: experimental group was implanted with hydroxyapatite material to establish the model of chick embryo chorioallantoic membrane carrying hydroxyapatite; control group was implanted with filter paper material, sealed and placed into a constant temperature and humidity box to continue to hatch. At the 12th day of incubation, length of new vessels and length of new vessels per unit area in the two groups were observed, and the angiogenesis on the hydroxyapatite and filter paper was observed. RESULTS AND CONCLUSION: The mean length of new vessels and length of new vessels per unit area were 24.031 mm and 0.242 mm/mm2 in the experimental group, and 23.561 mm and 0.212 mm/mm2 in the control group, respectively. There were no significant differences between two groups. Additionally, vascular tissues were obviously observed on the hydroxyapatite samples in the experimental group. These experimental results show that the establishment of the model of chick embryo chorioallantoic membrane carrying hydroxyapatite provides a simple and accurate in vitro animal model for studies on ideal bone graft materials and angiogenesis. The hydroxyapatite has no effect on the angiogenesis on the chorioallantoic membrane. [ABSTRACT FROM AUTHOR]