Toxicity assessment of nanosilver wound dressing in Wistar rat.

Antibiotic resistance to microorganisms is one of the major problems faced in the field of wound care in burns patients. Silver nanoparticles have come up as potent antimicrobial agent and are being evaluated in diverse medical applications ranging from silver based dressings to silver coated medical devices. We aimed in present study to test the release of nanosilver from nanosilver wound dressing and compare the dermal and systemic toxicity of nanosilver dressings in a repeated dose (21 days) model. Under general anesthesia, a limited standard 2nd degree burns were provided on the back of each rat in all treatment, negative control (simple dressing) and 5% silver nitrate groups, each contained 5 male wistar rats. According to the analysis made by atomic absorption spectrometry, the wound dressings released 0.599 ± 0.083 ppm of nanosilver during first 24 hrs of study. Daily observations were recoded and wounds were covered with new dressings each 24 hrs. Burn healing was observed in nanosilver wound dressing group in shorter time periods than the control groups. In toxicity assessment, this dressing didn't cause any hematological and histopathological abnormalities in treatment group but biochemical studies showed significant rise of plasma transaminase (ALT) at the endpoint (21 days) of the study (P=0.027). Portal mononuclear lymphoid and polymorphonuclear leukocyte infiltrations in three to four adjacent foci were recognized around the central hepatic vein in treatment group. Mild hepatotoxic effects of nanosilver wound dressing in wistar rat emphasize the necessity of more studies on toxicity potentials of low dose nanosilver by dermal applications.