Effect of standardized extract of centella asiatica eca 233 on incision wound healing in non-diabetic and diabetic rats

Abstract

The present study aimed to evaluate the effect of topically applied ECa 233, a standardized extract of Centella asiatica, on incision wound healing in non-diabetic and diabetic rats. Determination of tensile strength, total collagen content, epidermal thickness and histological observation were made on day 3 and 7 post wounding. On day 3 post wounding, tensile strength in non-diabetic rats treated with 0.05% ECa 233 (5.33 ± 1.78 N/cm²) was significantly increased in comparison to those untreated (2.40 ± 0.41 N/cm²) and gel base treated groups (2.31 ± 0.39 N/cm²). Epidermal thickness of all animals treated with 0.05%, 0.1% and 0.5% of ECa 233 (158.13 ± 11.38 µm, 117.71 ± 6.33 µm, 114.58 ± 8.25 µm) was significantly higher than in those of untreated (81.13 ± 7.23 µm) and gel base treated groups (88.25 ± 9.66 µm). In addition, a distinct fibroblast proliferation as well as granulation tissue was clearly observed in 0.05% ECa 233 treated groups whereas they were sparsely observed on the others. However, no significant difference was found on collagen content of all groups. Despite significant differences observed on day 3, no significant difference among groups was demonstrated on any parameters measured at day 7. The results observed hereby clearly suggest wound healing activity of ECa 233 0.05%. Effectiveness of topically applied ECa 233 was also demonstrated on incision wound in diabetic rats, however, with a delay of onset. Wound healing in all experimental groups of diabetic rats were comparable on day 3 whereas comparatively significant increase of tensile strength and epidermal thickness in 0.05% ECa 233 treated group were seen on day 7. Tensile strength of 0.05% ECa 233 treated group was found to be 12.77 ± 1.45 N/cm² on day 7 whereas they were 7.55 ± 0.36 N/cm² and 6.98 ± 0.95 N/cm² in untreated and gel base treated groups, respectively. Histological evaluation demonstrated significantly increased of epidermal thickness (137.54 ± 1.92 µm), fibroblast proliferation and granulation tissue in 0.05% ECa 233 treated groups in comparison to the others whereas no significance was observed on collagen content. Higher level of oxidative stress in diabetes may underlie a delayed onset of healing activity in diabetic rats. However, the mechanism that accounted for the healing effects in both non-diabetic and diabetic rats seem to be similar. Dissociation between collagen content and tensile strength excludes stimulating effect on collagen synthesis. 0.05% ECa 233 seems to exert its healing effects on incision wound at least, in part, by a stimulation of epithelialization seen as an increase in epidermal thickness. Some other underlying mechanisms remain to be further investigated.