OBJECTIVETo study the distribution and expressions of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in the III-IV stage of pressure ulcer wound, and to explore their correlation with ulceration.

METHODSForty-one patients hospitalized in the two Affiliated Hospital of Wenzhou Medical College from June 2010 to March 2012 were recruited, including twenty-one patients with 23 pressure ulcer of stage III-IV, 14 acute injury patients, and 6 donors of normal skin. Samples harvested from the 41 patients through surgery were divided into four groups, including pressure ulcer centre group (n = 23), pressure ulcer margin group (n = 23), acute wound group (n = 14), and normal skin group (n = 6). The histological changes in wounds were observed after HE staining. The distribution of collagen fiber in wound was observed with Masson staining. Expressions of VEGF and bFGF in wounds were detected with immunohistochemical staining. Data were processed with independent samples t test and paired samples t test.

RESULTS(1) In the two pressure ulcer groups, large number of inflammatory cells were found in aggregation; the expression of collagen fiber was decreased or disappeared; the positive expressions of VEGF and bFGF were mainly located in fibroblasts and endothelial cells. The expression levels of VEGF and bFGF were respectively 100 ± 39, 132 ± 46 in pressure ulcer centre group, and 228 ± 48, 299 ± 80 in pressure ulcer margin group. The differences between the two pressure ulcer groups were statistically significant (with t values respectively 13.497 and 13.020, P values below 0.01). (2) In acute wound group, a large number of fibroblasts but a small amount of collagen fibers were observed; the positive expressions of VEGF and bFGF were mainly located in fibroblasts, with respective expression levels of 292 ± 59 and 443 ± 194, which were significantly higher than those of the two pressure ulcer groups (with t values from 2.370 to 11.570, P < 0.05 or P < 0.01). (3) In normal skin group, structure of tissue was appropriate, and abundant collagen fibers were observed; the expression levels of VEGF and bFGF were respectively 45 ± 18 and 54 ± 22, which were significantly lower than those of the other three groups (with t values from 3.983 to 14.087, P values all below 0.01).

CONCLUSIONSIn contrast with those of the acute wounds, the expression levels of VEGF and bFGF are significantly decreased in the pressure ulcer wound at stage III-IV. It may be closely correlated with the decrease or cessation of the synthesis of collagen fiber.