The antibacterial and anti-inflammatory effects of zinc oxide nanoparticles synthesized by Thymus vulgaris medicinal plant against Escherichia coli and Escherichia coli lipopolysaccharides

Background and objectives The emerging nanotechnology-prepared medications and their applications in industrial and medical fields have gained great progress. This study aimed to investigate the efficacy of zinc oxide nanoparticles (ZnO-NPs) synthesized by the green method using the Thymus vulgaris plant extract against the most common pathogenic bacteria causing endometritis in horses (Escherichia coli) and E. coli lipopolysaccharide (LPS). Materials and methods Uterine swabs from mares (n=50) with clinical endometritis were collected for isolating the pathogenic bacteria. A total of 40 Wistar rats were divided equally into control (n=10), LPS (n=10; 10 mg/kg body weight), ZnO-NPs (n=10; 50 mg/kg body weight), and LPS+ZnO-NPs (n=10). ZnO-NPs were administered for 4 days and the LPS on the fourth day. Histopathological and ultrastructures of liver, kidney, and testes were obtained. Blood samples were collected for measuring superoxide dismutase (SOD), malondialdehyde, nitric oxide, and testosterone. Results and conclusion ZnO-NPs of 15–30 nm showed antimicrobial effectiveness against the isolated multidrug-resistant E. coli. The LD50 for ZnO-NPs was 2000 mg/kg body weight. The histopathological changes showed massive damage to the seminiferous tubules, liver, and kidney of LPS-treated rats, which was reversed to a great extent by preadministration of ZnO-NPs. The activity of SOD was high in LPS and ZnO-NPs, but the LPS+ZnO-NPs and the controls had the lowest SOD activity. LPS and LPS+ZnO-NPs decreased malondialdehyde concentrations. LPS decreased NO, but ZnO-NPs restored control values. Testosterone declined after LPS administration, with no observed changes in the rats treated with ZnO-NPs or LPS+ZnO-NPs. ZnO-NPs proved dual actions of antimicrobial and anti-inflammatory. Short course and suitable dose should be investigated to avoid its cytotoxicity effects to vital organs.