Beneficial effects of aminoguanidine on skin flap survival in diabetic rats

Abstract

Random flaps in DM patients have poor reliability for wound coverage, and flap loss remains a complex challenge. The protective effects of aminoguanidine (AG) administration on the survival of dorsal random flaps and oxidative stress were studied in diabetic rats. Two months after the onset of DM, dorsal McFarlane flaps were raised. Forty rats were divided into four groups: (1) control, (2) AG, (3) DM, and (4) DM + AG groups. Flap viability, determined with the planimetric method, and free-radical measurements were investigated. In addition, HbA1c and blood glucose levels, body weight measurements, and histopathological examinations were evaluated. The mean flap necrotic areas (%) in Groups I to IV were 50.9 ± 13.0, 32.9 ± 12.5, 65.2 ± 11.5, and 43.5 ± 14.7, respectively. The malondialdehyde (MDA) and nitric oxide (NO) levels were higher in the DM group than in the nondiabetic group, while the reduced glutathione (GSH) levels and superoxide dismutase (SOD) activity were reduced as a result of flap injury. In the diabetic and nondiabetic groups, AG administration significantly reduced the MDA and NO levels and significantly increased GSH content and SOD enzyme activity. We concluded that AG plays an important role in preventing random pattern flap necrosis.

Figure 1

Flap necrosis area in the groups.

Figure 2

Appearance of rat dorsal random pattern flaps 7 days after surgery, (a) control group, (b) AG group, (c) DM group, and (d) DM + AG group. The photographs show samples of flap necrosis and survival areas in the corresponding groups.

Figure 3

Light microscopy of the skin flaps (Masson's trichrome stain). Control group (a, e, i), AG group (b, f, j), DM group (c, g, k), DM + AG group (d, h, l). Comparison of hair follicles among the four groups (a, b, c, d), comparison of fibroblasts among the four groups (e, f, g, h), comparison of inflammation among the four groups (i, j, k, l). In the AG group (b, f), in the number of hair follicles (MT ×100) and in the cytological appearance of the fibroblasts (MT ×400), no significant difference was observed when compared to the control group (a, e). In the DM group (c), a significant decrease in the number of hair follicles (MT ×100) and dermal atrophy features including reduced dermal thickness, cytologically more rounded appearance of fibroblasts (MT ×400), and slightly irregular collagen structure was observed when compared to the control group (e). Inflammation and necrosis were more apparent in the DM groups (k, l) (MT ×100).