Abstract
Blue-green microalga Spirulina platensis (SP) gained more attention for its antioxidant and/or anti-inflammatory properties magnifying its beneficial effects as a feed additive and for cosmetic and biomedical applications. This study was performed to examine the impact of SP on the cutaneous wound and burn healing and to develop an understanding of the correlation between the sequelae of wound healing and the molecular expression patterns of wound healing-related genes as angiogenic basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) and fibrosis-related genes as transforming growth factor-beta (TGF-beta) and alpha-smooth muscle actin (alpha-SMA) in rat wound models. To achieve these goals, two experiments were performed on 32 Wister male rats that were divided into 4 groups of 8 rats each. Each experiment was represented by 2 groups; the control group (CG) and the Spirulina group (SG). A full-thickness wound (1.5 x 1.5 cm) and burn wound (2 x 2 cm) were made on the back of each generally anaesthetized rat and the areas of wound and burn were measured on days of 0, 3, 6, 9, 12, and 15 and 0, 3, 6, 9, 12, 15, 18, and 21 post-wound and post-burn respectively. In both experiments, SP was topically applied on the backs of wounded and burned rats in Spirulina treated groups. The phases of wound granulation tissues were detected histopathologically. Immunohistochemistry was used to determine the expressions of (TGF-B1) and (VEGF). Furthermore, the relative quantification of gene expression was implemented using the (bFGF), (VEGF), (TGF-B1), and (alpha-SMA) as target genes. Histopathological examination revealed inflammatory cell infiltration, angiogenesis, epithelialization, and extracellular matrix deposition and wound contraction in SG as compared to CG in both experiments. Immunohistochemistry results showed a significant improvement in the VEGF and TGF-beta 1 expression levels of SG in both experiments. Interestingly, SG in both experiments revealed upregulation of angiogenic genes (bFGF and VEGF) and downregulation of fibrotic genes (TGF-beta 1 and alpha-SMA). In conclusion, our findings suggest that the topically applied Spirulina promoted wound healing. Thus, SP can be used as a biomedical application to treat various skin wounds and may reveal a potential molecular basis for future promising antifibrotic agents against scar formation.