RÉSUMÉ
BACKGROUND:Animal models of diabetic encephalopathy that have been studied mainly include streptozotocin-induced model,high-sugar and high-fat diet-induced model and spontaneous animal model.Establishing a simple,easy,short-cycle,safe and effective model of diabetic encephalopathy can help to explore the subsequent pathogenesis and screen therapeutic drugs. OBJECTIVE:To further explore and evaluate the method of building diabetic encephalopathy rat models. METHODS:Twenty Sprague-Dawley rats were randomly divided into control(n=10)and model(n=10)groups.Rats in the model group were given a single injection of 45 mg/kg streptozotocin in the left lower abdominal cavity,and those in the control group were given the same amount of citrate buffer.During the experiment,the body mass,feed intake,water intake and blood glucose were measured.After 8 weeks,the glucose tolerance and oxidative stress levels were measured,and the pathological changes of brain tissue and the expression of apoptotic proteins were compared between groups. RESULTS AND CONCLUSION:Compared with the control group,the food intake,water intake,encephalization quotient,blood glucose and area under the blood glucose curve were significantly increased in the model group,while the body mass decreased significantly(P<0.01).Histopathological examination of the brain showed that compared with the control group,the number of surviving nerve cells was significantly reduced in the model group(P<0.01),with more significant pathological damage of nerve cells.Compared with the control group,the activities of serum superoxide dismutase,catalase and glutathione in the model group were significantly decreased(P<0.01),and the content of oxidative malondialdehyde was significantly increased(P<0.05).The expression levels of apoptosis-related proteins Bax and Caspase-3 in brain tissue increased in the model group compared with the control group,while the expression of Bcl-2 decreased(P<0.01).In conclusion,an 8-week injection of 45 mg/kg streptozotocin can cause obvious pathological damage to the brain tissue of diabetic rats,to successfully establish the rat model of diabetic encephalopathy.
RÉSUMÉ
BACKGROUND:Combined radiation and wound injury appeared mainly in patients with tumor radiotherapy and nuclear radiation accidents.The radiation destroys the repair mechanism,resulting in delayed or prolonged wound healing.It still lacks an effective therapeutic strategy currently. OBJECTIVE:To prepare multifunctional wound dressings based on the multiple clinical symptoms of combined radiation and wound injury,which are designed to be antibacteria,promoted healing and analgesics. METHODS:Using levofloxacin,fibroin and lidocaine hydrochloride as raw materials,3D bioprinting technology was applied to prepare the multifunctional wound dressing.(1)The multifunctional dressing was placed on a fixed culture plate coated with Staphylococcus aureus,Escherichia coli and Pseudomonas aeruginosa,and incubated at 37 ℃ overnight to detect the diameter of the antibacterial zone.(2)40 Kunming mice were randomly divided into trauma group,radiation and trauma model group,treatment group and positive drug group,with 10 mice in each group.Mice in the radiation and trauma model group,treatment group and positive drug group were irradiated by 60Co gamma rays.After 1 hour of radiation,a full-layer skin defect wound with a diameter of 1 cm was made on the back of each mouse in the four groups.Normal saline was applied to the wounds of the trauma group and the radiation and trauma model group.Trethanolamine cream was applied to the wounds of the positive drug group.Multifunctional dressing was applied to the wounds of the treatment group.The dressing was changed every 2 days,and the treatment was continued for 14 days.Wound healing rate and serum interleukin-6 level were measured at 3,7 and 14 days after wound modeling.14 days after the wound modeling,the skin tissue of the wound was obtained and received hematoxylin-eosin staining,Masson staining and cytokeratin-14 immunohistochemical staining. RESULTS AND CONCLUSION:(1)3D-printed multifunctional wound dressing had good antibacterial activity.The antibacterial zone diameters against Staphylococcus aureus,Escherichia coli and Pseudomonas aeruginosa were(4.15±0.09),(4.18±0.23)and(4.35±0.13)cm,respectively.(2)With the extension of modeling time,the wound healed gradually.The wound healing rate of the treatment group and the positive drug group was higher than that of the radiation and trauma model group at 3,7 and 14 days after modeling(P<0.01,P<0.001).The wound healing rate of the treatment group was higher than that of the positive drug group.With the extension of modeling time,the serum interleukin level of mice increased first and then decreased.The serum interleukin level in the treatment group at 3,7 and 14 days after modeling was lower than that in the radiation and trauma model group.Hematoxylin-eosin staining and Masson staining exhibited that inflammatory cells infiltrated the granuloma tissue in the trauma group,and the dermal collagen fibers were densely arranged.The normal structure of epidermis and dermis was destroyed and inflammatory cells were infiltrated in the radiation and trauma model group.In the treatment group,normal skin mucosal tissue was observed,the epidermis was arranged closely,and the sweat glands,hair follicles and dermal collagen fibers were arranged regularly.In the positive drug group,the arrangement of epidermal layer was tight,and the arrangement of sweat glands,hair follicles and dermal collagen fibers was regular.Cytokeratin-14 immunohistochemical staining displayed that the epidermal tissue thickness in the treatment group was lower than that in the other three groups(P<0.01,P<0.001).(3)The results confirm that the 3D-printed multifunctional dressing has multiple functions of local anesthesia,anti-infection and promoting healing.