| Objective: Establish an animal model of diabetic ulcer and focus on the MMPs/TIMP system,explore the mechanism of skin regeneration medical technology(Moist exposed burn therapy,MEBT/ Moist exposed burn ointment,MEBO)to promote the wound healing of diabetic ulcer,provide a theoretical basis for MEBT/MEBO to intervene in diabetic ulcer wound repair and further guide the clinical practice.Methods: Hundred and ten male SD rats were randomly divided into normal group(n=24)and diabetic group(n=86).Diabetic group were fed with high-fat-sugar diet for 4 weeks and then induced by intraperitoneal injection of streptozotocin(STZ).If random blood glucose ≧ 16.7 mmol/L and significant weight loss after modululation,it was seen as successful induction in the diabetic model.Then selected seventy-two diabetic rats with successful modeling and randomly divided into model group,MEBO group,and b FGF group(n=24 each).The normal rats divided into blank group(n=24).Ulcer wound models were prepared in each group.All rats marked a 18-mm-size in the back,and underwent full-thickness skin resection.The wounds were changed of dressing daily for 12 days.Wound healing were dynamically observed and wound tissues were collected at three time points(4d,6d and12d)for Masson staining,RT-PCR and Western Blot.Results:(1)Weight and blood glucose: Before establishing diabetic model,there was no significant difference in weight and blood glucose in normal group and diabetic model group.After modeling,the blood glucose in the diabetic model group was significantly higher than the normal group and the weight was decreased,the differences were statistically significant(P<0.01).(2)Wound healing rate: On days 4,6 and 12,the wound healing rate in the model group was evidently lower than that of the blank group,the differences was statistically significant(P<0.01)and the MEBO group and b FGF group were significantly increased compared with the model group(P<0.01).(3)Wound pathology: On days 4 and 6,the model group had less collagen and more inflammatory cells,while the blank and MEBO groups had more collagen and less inflammatory.On day 12,the collagen fibers in the blank group were rich and well arranged;the MEBO group and b FGF group were relatively regular;the model group had uneven collagen thickness and structural disorder.On days 4,6 and 12,the collagen level of wound tissue in the model group was decreased than the blank group(P<0.01).The collagen level in the MEBO group was significantly increased than the model group(P<0.01).(4)Result of q RT-PCR: On days 4 and 6,MMP-3 and MMP-13 m RNA expression level in model group were higher than the blank group(P<0.05),MMP-3,MMP-13 m RNA in the MEBO and b FGF group were lower than the model group(P<0.01).On day 12,the expression levels of MMP-3,MMP-8,and MMP-13 m RNA in the model group were higher than the blank group(P<0.01),MMP-3,MMP-8,MMP-13 m RNA in the MEBO group were lower than the model group(P<0.01),MMP-3 and MMP-8m RNA in the b FGF group were higher than the model group(P<0.01).On days 4,6 and 12,TIMP-1 and TIMP-2 m RNA in the model group were lower than the blank group(P<0.05),TIMP-1 and TIMP-2 m RNA in the MEBO group were higher than the model group(P<0.05).On days 4 and 12,TIMP-1and TIMP-2 m RNA in the b FGF group were higher than the model group(P<0.01).(5)Result of western blot:On days 4,6 and 12,MMP-3,MMP-8 and MMP-13 protein expression level in the model group were higher than the blank group(P<0.05),MMP-3,MMP-8 and MMP-13 in the MEBO were lower than the model group(P<0.05),MMP-3 and MMP-8 in the b FGF group were lower than the model group(P<0.01).On day 6 and 12,TIMP-1 and TIMP-2 in the model group were lower than the blank group(P<0.05),TIMP-1 and TIMP-2 in the MEBO group were higher than the model group(P<0.05).On day 6,TIMP-1 and TIMP-2 in the b FGF group were higher than in the model group(P<0.01),on day 12,TIMP-2 in the b FGF group was higher than in the model group(P<0.01).Conclusion:(1)MEBT/MEBO can improve the wound healing rate of diabetic ulcers rats and effectively promote the wound healing of diabetic ulcers rats.(2)MEBT/MEBO can reduce MMP-3,8,13 m RNA and protein expression levels in the wound tissue of diabetic ulcer rats,improve TIMP-1,2m RNA and protein expression levels,increase collagen fiber expression levels,regulate MMPs/TIMP system and the dynamic balance of the extracellular matrix,thus promoting diabetic ulcer wound healing.MEBO/MEBT regulating MMPs/TIMP balance may be one of the mechanisms to promote diabetic ulcer wound healing. |
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