Influence of pullulan hydrogel on sutureless wound healing in rats

Carbohydrate polymers have been used to make wound dressings since many years. Pullulan is a carbohydrate polymer, found abundant in nature, produced by various strains of Aureobasidium. In this study, pullulan hydrogel (10%) has been used to test its healing efficacy on suture-less wounds in rats. Male Wistar rats weighing between 150 and 200 g body weights were used for this study. The animals were divided into 3 groups, each group comprising of six animals and a 3 cm full thickness incision was made on the dorsum of the rats. To group I rats, 500 μl of the hydrogel was applied on the wounds followed by finger clamping for 2 min. Group II (positive control) rats were applied with povidone-iodine and group III rats (control) were left untreated. The drug was given once a day until the wounds healed completely. The healing rate was assessed by observing the number of days required for complete healing. The incision wounds of hydrogel treated rats healed within 6 days whereas the wounds of positive control and control rats had taken 11 days and 15 days respectively, for complete healing. The animals were sacrificed and wound breaking strength of the incisions was measured. A two fold increase in the tensile strength was observed in the pullulan hydrogel treated wounds when compared to the control and positive control wounds. The tensile strength of pullulan hydrogel treated wounds was found to be (3.63 MPa) when compared to control (1.17 MPa) and positive control (1.34 MPa) rats. Shrinkage temperature was also remarkably augmented (more than 25%) when compared to control. Histopathological evaluations showed enhanced proliferation of fibroblasts and faster epithelialization of wounds in pullulan hydrogel treated rats. The increased rate of healing in pullulan hydrogel treated wounds might be due to its energy giving and anti-oxidant properties.