Chloramphenicol‐Induced Oxidative Stress in Human Neutrophils

Abstract

The aim of this study was to evaluate the in vitro effect of chloramphenicol in order to determine its potential toxic effects on human neutrophils, by using assays of reactive oxygen species (ROS) determination, nitrite measurement and antioxidant systems. Chloramphenicol enabled the oxidative stress response of neutrophils and increased the ROS production at 2, 4, 8 and 16 μ g/ml, while ROS generation decreased at high concentrations (32 μ g/ml). The nitroblue tetrazolium assay shows that neutrophils incubated with chloramphenicol increased the intracellular ROS, with the extracellular production rising with a corresponding increase in antibiotic concentration. Enzymatic activities -superoxide dismutase, catalase and diaphorase enzymes -increased after chloramphenicol treatment, while the glutathione level decreased in neutrophils incubated with antibiotic. The results obtained in the present work suggest that the study of susceptibility to oxidative stress in neutrophils before chloramphenicol treatment could be adequate for in vitro toxicity screening.Oxidative stress has been associated with hepatic and renal toxicity [1], but leucocytes can also be affected in the reactive oxygen species (ROS) production by toxic substances [2]. The regulation of ROS production is particularly important in neutrophils, because these cells perform an important function in host defence against bacterial infections by producing ROS and nitrogen species, hydrolytic and proteolytic enzymes, and antimicrobial polypeptides. Although neutrophils also produce nitric oxide, the levels are low and likely to result from the activity of a constitutive nitric oxide synthase [3]. Deregulation of nitric oxide and increased oxidative and nitrosative stress are implicated in tissue damage [4].Several chemical agents can alter the cellular functions associated with the oxidative metabolism, thereby stimulating ROS production in neutrophils [5]. Antibiotics have various side effects, and some of them may influence the functions of neutrophils [6]. Free radical reactions have been suggested to be involved in the toxic effects of several antibiotics [7][8][9][10][11]. Idiosyncratic aplastic anaemia can occur in predisposed patients after chloramphenicol, irrespective of the dosage. This is thought to be due to the production by the gut flora of a nitro-reduction derivative of chloramphenicol. This derivative can induce DNA damage in replicating haematopoietic stem cells, resulting in marrow hypocellularity and progressive pancytopaenia [12]. The most common presentation, however, is a reversible, dose-dependent bone marrow suppression, which usually occurs when serum chloramphenicol levels exceed 25 mg/l for prolonged periods of time. This condition is associated with the inhibition of mitochondrial protein synthesis, and is characterized by mild marrow hypocellularity, anaemia, neutropaenia and thrombocytopaenia [13]. As non-idiosyncratic aplastic anaemia and 'grey baby' syndrome are dose-dependent complications of chloramphenicol us...

Distribution, detection of enterotoxigenic strains and antimicrobial drug susceptibility patterns of Bacteroides fragilis group in diarrheic and non-diarrheic feces from Brazilian infants

“…In Brazil, there is a lack of scientific data on the incidence of ETBF in the population; however, data show the incidence of these microorganisms in HIV-positive children (3.1%) (8) The use of chloramphenicol has been declining in many countries due to the toxicity of the drug, which causes intestinal disorders, depression and anemia. On the other hand, in our country, this drug is consumed widely and in our study a high rate of resistance was observed for this antimicrobial (7,12,26). According to the literature, in the regions where the drug is still used for the treatment of infections in which BFG is involved, levels of resistance to chloramphenicol are up to 11%, though not all authors considered intermediary resistance (7,20).…”

Efficacy of Some Antibiotics in Curing Resistant <i>Escherichia coli</i> Infection

“…Chloramphenicol has been demonstrated to affect the oxidative state of cellular components by increasing the intracellular ROS, while the glutathione level decreased in neutrophils [94] [109].…”

“…Also tenoxicam-treated patients had a significant decrease in nitrite levels [93]. But chloramphenicol increases nitrite production in neutrophils incubated with a corresponding increase in antibiotic concentration [94]. Thus inhibition of NO production paid attention to the anti-inflammatory activity of erythromycin.…”

Scientific Opinion on Chloramphenicol in food and feed

“…The importance of the nitroso moiety of nitroso-chloramphenicol was evidenced by the lack of DNA damage seen when nitroso-chloramphenicol was replaced by chloramphenicol. Paez et al (2008) found that chloramphenicol at concentrations of 2-16 μg/mL increased the production of reactive oxygen species (ROS) in isolated human neutrophils in vitro. The activity of SOD, CAT and diaphorase was increased at these concentrations.…”

“…It is relevant to note that multiple biotransformation routes, i.e. the nitroreductive one, as well as the CYP-mediated oxidative dehalogenation and the glutathionedependent dechlorination, are thought to generate oxygen and nitrogen radical species playing a pivotal role in a number of chloramphenicol-mediated adverse effects (Paez et al, 2008;Oyagbemi et al, 2010).…”