Systemic Effects of Repeated Intraperitoneal Application of Graphene Oxide and Polyethylene Glycol-Functionalized Graphene Oxide Nanoparticles in Long Evans Male Rats

Recently, nanosized graphene oxide (nGO) has gained significant scientific interest in biomedical strategies. However, before clinical translation, GO-based nanomaterials must be thoroughly evaluated for safety and biocompatibility. Therefore, this study investigated the in vivo effects of pristine GO and polyethylene glycol-functionalized GO (nGO-PEG) nanoparticles in male Long Evans rats, following repeated intraperitoneal administration (4 mg/kg body weight). The effects of the nanoparticles were assessed using a range of physiological and pathological markers including body weight (BW) gain, organ coefficients, diuresis, histological, hematological and biochemical parameters. Both nGO and nGO-PEG significantly suppressed BW gain and reduced diuresis in treated rats. Nanoparticle exposure resulted in significant kidney enlargement and reduced testes weight. Mild histological alterations were observed in all examined organs, with nGO showing a tendency toward slightly more pronounced changes than nGO-PEG. Serum levels of aspartate aminotransferase, alanine aminotransferase, and creatinine were significantly elevated in nGO-treated rats, whereas nGO-PEG significantly increased the urinary levels of creatinine and urea. Both nGO- and nGO-PEG-treated rats exhibited elevated serum glucose concentrations. Significant hematological changes were detected in rats treated with both nanoparticles with pronounced effects observed following nGO-PEG administration. Our results suggest possible hematological and metabolic disturbances, as well as hepatic injury and renal toxicity in rats at repeated exposure to nGO and nGO-PEG.