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Objective To explore the possible mechanism of NGF mixed Insulin on the angiogenesis of burn wounds and effect on the expression of bcl-2 and bax in diabetic rats.Methods 60 SPF male Wistar rats, weighting 200-220g, Streptozotocin (STZ) was given to rats by intraperitoneal injection 10 mg/kg on the first day, and 50 mg/kg on the third day. Then these rats were randomly divided into scalding of the rats with diabetes (B), n=15; insulin control(C), n=15; NGF control(D); n= 15; NGF and insulin control (E), n= 15 groups. Group (A) (normal control.n=15). and Deep partial thickness scalding was engendered on the back of the rats after one month. After that wound in group A and B applied 3 layer gauze with NS,2/d. Wound in group C applied 3 layer gauze with 5 U Novolin 30R(40 IU/mL) 2/d and gave Novolin 30R (4～6) U/kg subcutaneous injection everyday. Wound in group D applied 3 layer gauze with 5 mL NGF (25 U/mL),2/d. Group E applied 3 layer gauze with 5 U Novolin 30R(40 IU/mL) and 5 mL NGF (25 U/mL) 2/d,and gave Novolin 30R (4～6) U/kg subcutaneous injection everyday. The wound area, wound healing rate, and microvascular density with CD34 immunohistochemistry staining were determined on 3rd,7th,15th, and 21st post scalding days (PSDs). In addition, the amount of bcl-2 and bax expressed on the wound vascular endothelial cells were determined on the above time points.Results In all groups the areas of wounds get smaller gradually with time. Each time points, compared to those in groups A、B、C and D, the wound healing rate in group E increased significantly since the 7th PSD [(25.33±2.32)%,(P<0.05)]., Compared to group B, Group C and D increased significantly since the7th PSD [(16.68±1.95)%, (P<0.05)] [(18.29±1.70)%,%,(P<0.05)], Compared to group A, group D increased significantly since the7th PSD [(54.84±3.60)%,(P<0.05)].The expression of bcl-2 increased gradually till peak on 15 day and descended from than on. From 7 day, Bax began to express in each group and increased gradually, bax in group E obviously lower than other group. Compared to those in groups A, B, C and D, the expression of CD34 and bcl-2 on the wound vascular endothelial cells cell in group E increased significantly, while the expression of bax decreased significantly (P<0.05). Furthermore, the wound MVD value was increased significantly at all post burn time points.Conclusions Combination of NGF and insulin local application could be beneficial to the angiogenesis in the burn wound of the rats with diabetes, as well as to accelerate wound healing
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