Effects of nerve growth factor mixed insulin on angiogenesis of burn wounds and expressions of Bcl-2 and Bax in diabetic rats
Zhang, J.; Xue, X.; Xie, P.; Chang, F.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 25(3): 354-360
2011
ISSN/ISBN: 1002-1892 PMID: 21500593 Document Number: 648026
To explore the possible mechanism of nerve growth factor (NGF) mixed insulin on the angiogenesis of burn wounds and the effect on the expressions of Bcl-2 and Bax in diabetic rats. A total of 75 SPF male Wistar rats, weighing 200-220 g, were selected randomly and divided into nomal control (group A, n = 15), the rats with diabetic control (group B, n = 15), insulin treatment (group C, n = 15), NGF treatment (group D, n = 15), NGF and insulin treatment (group E, n = 15) groups. In groups B, C, D, and E, streptozotocin was given by intraperitoneal injection at dose of 10 mg/kg on the 1st day and 50 mg/kg on the 3rd day to prepare the diabetic rat models. In group A, citric acid buffer at the same dose was given. After 1 month of diabetic models, second degree scald was made on the back of the rats, and then wounds were treated with 3-layer normal saline gauze in groups A and B, with 3-layer gauze containing 5 U Novolin 30R and subcutaneous injection of Novolin 30R (4-6 U/kg) everyday in group C, with 3-layer gauze containing 5 mL NGF (25 U/mL) in group D, and with a combination of groups C and D in group E. At 7, 11, 15, and 21 days, the wound healing rate was calculated; at 3, 7, 11, 15, and 21 days, the expressions of Bcl-2, Bax, and CD34 were determined and the microvascular density was measured by immunohistochemistry staining. All rats survived till experiment was finished. The area of wounds became smaller gradually with time. Group E was better than other groups in the wound healing rate (P < 0.05), the skin keratosis, the hair growth, and the granulation tissue and collagen fibers growth. With time, the expressions of CD34 and Bcl-2 increased gradually, reached the peak at 15 days and decreased at 21 days; the expression was stronger in group E than in other groups (P < 0.05). At 3 days, Bax did not express; at 7 days, Bax began to express in new vascular endothelial cells and the expression increased gradually with time; the expression was weaker in group E than in other groups (P < 0.05). A combination of NGF and insulin local application can enhance the angiogenesis of the burn wound in diabetic rats and accelerate wound healing by increasing the expression of Bcl-2 and decreasing the expression of Bax and restraining apoptosis of the wounds vascular endothelial cells of diabetic rats.