In vivo Antibacterial efficacy of a Novel Scorpion Venom Peptide Smp24 Conjugated with Bimetallic Nanomaterials

Abstract

The current research focused to evaluate the in vivo antibacterial efficacy of a new scorpion venom peptide, Smp24, via applying murine wound infection model challenging the Gram-positive bacterial strain Staphylococcus aureus for the first time. In addition, Smp24 peptide was combined with bimetallic nanoparticles (Silver and Copper oxide) to enhance its antibacterial properties. In vivo evaluation revealed noticeable skin lesions, localized swelling, and necrosis in the examined areas, which were qualitatively observed and monitored daily for 5 days regarding bacterial colonies, wound healing, and re-epithelialization. The results declared that Smp24 holds significant therapeutic promise against Staphylococcal skin infections, as most animals tested did not develop infection when using the peptide/strain combination. Cytokines analysis showed the nano-conjugate decreased pro-inflammatory systemic production levels (TNF-α/IL-6) and elevated anti-inflammatory cytokines (IL-4/IL-10) comparing to the native peptide and the positive control antibiotic Ampicillin (p<0.01). Oxidative stress assays indicated increased total oxidant capacity (TOC) and decreased total antioxidant capacity (TAC) in all treated mice, while the nano formulation moderated these changes, suggesting reduced oxidative damage (p<0.01). Moreover, the application of nanopeptide on the skin of mice provided superior protection rate from infection with a notably greater antibacterial efficacy compared to the other two applied ointments. This was quantitatively recorded through chemical assessments of oxidative status, measurements of pro/anti-inflammatory cytokines, and haematological studies of laboratory test animals, along with histopathological examinations of infected areas and daily morphological monitoring.