Influence of low power density on wound healing in streptozotocin-induced diabetic rats

Abstract

Photobiomodulation therapy (PBMT) is used for wound healing at two different power densities, i.e. 0.2 W cm-2 and 0.4 W cm-2, while maintaining the same fluence of 5 J cm-2. Forty-five streptozotocin (STZ)-induced diabetic rats were allocated into three groups: the untreated laser group (G0), 0.2 W cm-2 laser treated group (GL1), and 0.4 W cm-2 laser treated group (GL2). Six mm full thickness cutaneous wounds are created on the dorsal side of rats. A 808 nm diode laser irradiates the wound in GL1 and GL2 daily for 9 consecutive days. Groups GL1 and GL2 have the same total fluence but different power densities, 0.2 W cm-2 and 0.4 W cm-2, which results in stimulatory and inhibitory effects in wound healing, respectively. In group GL1, enhanced wound contraction and inflammation has been triggered at an earlier stage compared to the untreated laser group G0. Meanwhile, the laser treated group GL2 exhibits an escalated volume of inflammatory cells, and collagen synthesis is inhibited. Therefore, it can be concluded that PBMT has potential in promoting wound healing under the low power density (0.2 W cm-2) condition.