MODULATION OF THE INFLAMMATORY CYTOKINES AND CYTOPROTECTIVE ENZYME BY BILIRUBIN TREATMENT TO ENHANCE CUTANEOUS WOUND HEALING IN RATS

Inflammation is the main process of wound healing where expression of certain cytokines likes Interleukin-10 (IL-10) and Tumour necrosis factor ∝ (TNF ∝) plays an important role. In view of the antioxidant potential of bilirubin, the present study was aimed to evaluate time-dependent (day 3, 7, 14) wound healing effects of bilirubin ointment (0.3%) in excisional wound model in rats. Thirty-six acclimatized healthy male Wistar rats (120-150g) were divided into control and treated groups containing 18 rats each. Each group was further sub- divided into three sub-groups (day 3, 7 and 14 days, n= 6). The ointment base (soft paraffin 90%, lanolin 5% and hard paraffin 5%) and bilirubin ointment (0.3%) were applied topically once daily for 14 days in control and treated group respectively. The wound area was determined on days 3, 7, and 14. The mRNA expression of TNF ∝ gene and IL-10 gene were determined on days 3, 7 and 14 by Real Time PCR and their protein levels by ELISA method. The protein expression of cyto-protective enzyme HO-1 (Heme oxygenage-1) and growth factor VEGF (Vascular growth factor) was determined by western blotting method. The mRNA expression and protein level of TNF ∝ was significantly reduced and IL-10 was significantly increased whereas the expression of HO-1 enzyme and VEGF was significantly increased in treated group on days 3, 7 and 14. It may be concluded that the bilirubin has pro-healing potential.