Evaluation of the wound healing potential of isoquercetin-based cream on scald burn injury in rats

Abstract

Background: The present study was designed to evaluate the potential of isoquercetin-based cream formulation on scald burn wound injury in rats.

Methods: Four isoquercetin-based cream formulations viz. 0.01, 0.02, 0.04, and 0.06 % w/w were prepared. Cream base and standard anti-burn cream containing silver sulfadiazine were also used for comparison. Scald burn was given to rats by pouring water at 90 °C on a shaved dorsal area of 20 mm(2). Deep second-degree burn injury was produced which was evaluated for the next 21 days for the percentage of wound contraction and period of epithelialization. On day 21, the rats were sacrificed and histopathological slides were prepared using hematoxylin-eosin staining. Burned tissue was also screened for levels of oxidative stress using thiobarbituric acid reactive species (TBARS) and reduced glutathione (GSH) estimation.

Results: There was a significant increase in the percentage of wound contraction and a significant decrease in the period of epithelialization in isoquercetin-based cream-treated groups as compared with the control group. However, most significant results were obtained with isoquercetin 0.06 % w/w cream. Histologically, isoquercetin 0.06 % w/w cream treatment resulted in almost complete re-epithelialization and re-structuring of the wound tissue. There was a significant rise in TBARS and a decrease in GSH levels in the burn injury group which was reversed to a major extent by the application of isoquercetin-based cream.

Conclusions: The results indicate the wound healing potential of isoquercetin-based cream. Tissue biochemical studies indicate towards a possible role of free radical scavenging in the observed effects of isoquercetin in wound healing.

Keywords: Burn; Free radicals; Isoquercetin; Scald; Wound healing.

Fig. 1

Representative histological slides of skin wound tissue of various groups on day 21 after burn injury. a Sham group with no histological changes; b burn injury group slide is characterized by incomplete formation of epithelial layer, inflammatory tissue damage, and edema; c cream base-treated group showing significant inflammatory damage and tissue edema; and d 0.01 % isoquercetin-based cream-treated group showing significant healing of burned tissue. The cellular structure of dermal layers has been restored. The signs of necrosis have been limited to most extent, and the tissue is devoid of any peri-vascular infiltration into tissue spaces. e 0.02 % isoquercetin-based cream-treated group showing more re-structuring and re-organizing of burned tissue. The process of tissue necrosis appears halted and tissue spaces less widened. f 0.04 % isoquercetin-based cream-treated group showing partial reformation of the epithelial layer with signs of tissue re-structuring and healing. g 0.06 % isoquercetin-based cream-treated group showing almost complete formation and healing of the epithelial layer. Moreover, there is less edematous swelling of tissue. h Standard (silver sulfadiazine) cream-treated group characterized by significant tissue repair and re-structuring with little edematous fluid

Fig. 2

Changes in wound tissue TBARS after scald burn injury. The graph represents tissue levels of TBARS (mM/ml) in sham, burn injury control, cream base-treated, silver sulfadiazine (standard)-treated, and different isoquercetin-based cream-treated groups. Results are represented as the mean ± standard deviation; n = 6 per group. ^aSignificant change in the mean value as compared to the sham group with p < 0.05; ^bsignificant change in the mean value as compared to the burn injury group with p < 0.05

Fig. 3

Changes in wound tissue GSH after scald burn injury. The graph represents tissue levels of GSH (mM/ml) of sham, burn injury control, cream base-treated, silver sulfadiazine (standard)-treated, and different isoquercetin-based cream-treated groups. Results are represented as the mean ± standard deviation; n = 6 per group. ^aSignificant change in the mean value as compared to the sham group with p < 0.05; ^bsignificant change in the mean value as compared to the burn injury group with p < 0.05