RESUMEN
Liposomes are among the most studied nanostructures. They are effective carriers of active substances both in the clinical field, such as delivering genes and drugs, and in the food industry, such as promoting the controlled release of bioactive substances, including food preservatives. However, toxicological screenings must be performed to ensure the safety of nanoformulations. In this study, the nematode Caenorhabditis elegans was used as an alternative model to investigate the potential in vivo toxicity of nanoliposomes encapsulating the antimicrobial peptide nisin. The effects of liposomes containing nisin, control liposomes, and free nisin were evaluated through the survival rate, lethal dose (LD50), nematode development rate, and oxidative stress status by performing mutant strain, TBARS, and ROS analyses. Due to its low toxicity, it was not possible to experimentally determine the LD50 of liposomes. The survival rates of control liposomes and nisin-loaded liposomes were 94.3 and 73.6%, respectively. The LD50 of free nisin was calculated as 0.239 mg mL-1. Free nisin at a concentration of 0.2 mg mL-1 significantly affected the development of C. elegans, which was 25% smaller than the control and liposome-treated samples. A significant increase in ROS levels was observed after exposure to the highest concentrations of liposomes and free nisin, coinciding with a significant increase in catalase levels. The treatments induced lipid peroxidation as evaluated by TBARS assay. Liposome encapsulation reduces the deleterious effect on C. elegans and can be considered a nontoxic delivery system for nisin.
Asunto(s)
Antibacterianos , Nanopartículas , Nisina , Fosfatidilcolinas , Animales , Antibacterianos/toxicidad , Caenorhabditis elegans , Lecitinas , Liposomas , Nisina/toxicidad , Especies Reactivas de Oxígeno , Sustancias Reactivas al Ácido Tiobarbitúrico , Sistemas de Liberación de MedicamentosRESUMEN
Immunogenicity and toxicity of antimicrobial peptide P34 were evaluated in vivo. BALB/c mice were inoculated intraperitoneally with peptide P34 alone and associated with Freund's adjuvant. For acute toxicity testing, different concentrations of the peptide P34 (82.5, 165.0, 247.5 and 330.0mg/kg) were orally administered. To evaluate the sub-chronic toxicity the tested dose of 0.825 mg/kg/day of the peptide P34 or nisin were administered for 21 days. There were no hypersensitivity reactions or significant increase in antibody titer during the immunogenicity experiment or death of animals during the acute or sub-chronic toxicity tests. The LD(50) was higher than 332.3 ± 0.76 mg/kg. No significant changes in serum biochemical parameters were observed in the animals treated with the peptide P34 unlike nisin-treated group showed a significant increase in alanine transaminase levels in comparison to controls. The group treated with 0.825 mg/kg/day of nisin showed histological changes in the spleen, skin and liver. In the group treated with peptide P34 histological changes in the spleen were observed, with the presence of megakaryocytes. Few studies report the use of animal models to evaluate the in vivo toxicity of antimicrobial peptides and such investigation is an essential step to ensure it safe use in foods.
Asunto(s)
Nisina/toxicidad , Péptidos/toxicidad , Animales , Adyuvante de Freund/administración & dosificación , Dosificación Letal Mediana , Hígado/efectos de los fármacos , Hígado/patología , Masculino , Ratones , Ratones Endogámicos BALB C , Péptidos/administración & dosificación , Piel/efectos de los fármacos , Piel/patología , Bazo/efectos de los fármacos , Bazo/patologíaRESUMEN
The in vitro cytotoxicity of the antimicrobial peptide P34 was evaluated in different eukaryotic cells. The food-grade bacteriocin nisin was also analysed for comparison. Vero cells were treated with different concentrations (0.02-2.5 microg x ml(-1)) of antimicrobial peptide P34 and nisin. Cell viability and plasma membrane integrity were checked by MTT [3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide], NRU (Neutral Red dye uptake) and LDH (lactate dehydrogenase) assays. The EC50 values of the peptide P34 in MTT and NRU assays were 0.60 and 1.25 microg x ml(-1) respectively, while values of nisin found were 0.50 and 1.04 microg x ml(-1). In the LDH assay, the EC50 values were 0.65 and 0.62 microg x ml(-1) for P34 and nisin, respectively. The peptide P34 revealed similar haemolytic activity on human erythrocytes (5.8%) when compared with nisin (4.9%). The effects on viability, motility and acrosomal exocytosis of human sperm were also evaluated. Nisin and P34 showed similar effects on sperm parameters. The evaluation of cytotoxicity of antimicrobial peptides is a critical step to guarantee their safe use.