This study determined the comparative nephrotoxic potential of four trichloronitrobenzenes (TCNBs) (2,3,4-; 2,4,5-; 2,4,6-; and 3,4,5-TCNB) and explored the effects of antioxidants and biotransformation inhibitors on TCNB-induced cytotoxicity in isolated renal cortical cells (IRCC) from male Fischer 344 rats. IRCC were incubated with a TCNB up to 1.0 mM for 15–120 min. Pretreatment with an antioxidant or cytochrome P450 (CYP), flavin monooxygenase (FMO), or peroxidase inhibitor was used in some experiments. Among the four TCNBs, the order of decreasing nephrotoxic potential was approximately 3,4,5- > 2,4,6- > 2,3,4- > 2,4,5-TCNB. The four TCNBs exhibited a similar profile of attenuation of cytotoxicity in response to antioxidant pretreatments. 2,3,4- and 3,4,5-TCNB cytotoxicity was attenuated by most of the biotransformation inhibitors tested, 2,4,5-TCNB cytotoxicity was only inhibited by isoniazid (CYP 2E1 inhibitor), and 2,4,6-TCNB-induced cytotoxicity was inhibited by one CYP inhibitor, one FMO inhibitor, and one peroxidase inhibitor. All of the CYP specific inhibitors tested offered some attenuation of 3,4,5-TCNB cytotoxicity. These results indicate that 3,4,5-TCNB is the most potent nephrotoxicant, free radicals play a role in the TCNB cytotoxicity, and the role of biotransformation in TCNB nephrotoxicity in vitro is variable and dependent on the position of the chloro groups.
Chloronitrobenzenes are key chemical intermediates used in the manufacture of dyes, agricultural agents and industrial compounds. Although some data exists on the toxicity of mono- and dichloronitrobenzenes, there is a paucity of data on the toxicity profile of trichloronitrobenzenes (TCNBs). One of the target organs for mono- and dichloronitrobenzenes is the kidney. The purpose of this study was to examine the in vitro nephrotoxic potential of two TCNBs, 2,4,5-trichloronitrobenzene (2,4,5-TCNB) and 2,4,6- trichloronitrobenzene (2,4,6-TCNB), using freshly isolated rat renal cortical cells (IRCC), and to study potential mechanisms of bioactivation and toxicity. Briefly, IRCC were obtained from male Fischer 344 rats using a collagenase perfusion technique and incubated (~4 million cells/ml, 3 ml) with a TCNB (0.5 or 1.0 mM) or vehicle (dimethyl sulfoxide) for up to 90 min. In some experiments, cells were pretreated with an antioxidant (ascorbate, alpha-tocopherol, glutathione, N-acetyl-L-cysteine) or metabolizing enzyme inhibitor prior to a TCNB or vehicle treatment. Cytotoxicity was determined by measuring lactate dehydrogenase release. 2,4,6-TCNB induced cytotoxicity as early as 60 min and at 0.5 mM, while 2,4,5-TCNB did not induce cytotoxicity until 90 min at 1.0 mM. Antioxidant pretreatments were effective in reducing the toxicity induced by both TCNBS but were more effective against 2,4,5-TCNB. Cyclooxygenase inhibition reduced 2,4,6-TCNB, but not 2,4,5-TCNB, cytotoxicity, while inhibition of cytochrome P450, flavin monooxygenase and peroxidase activity were not protective. These results suggest 2,4,6-TCNB is more nephrotoxic than 2,4,5-TCNB and that free radicals contribute to TCNB nephrotoxicity in vitro.Supported in part by NIH grant P20GM103434.
Dichloroanilines (DCAs) and dichloronitrobenzenes (DCNBs) are important chemical intermediates in the manufacture of a wide variety of industrial, agricultural, and pharmaceutical agents and have been found to induce nephrotoxicity in vivo and/or in vitro. CAs may also be metabolized to CNBs and vice versa. Among the DCNBs, 3,5-dichloronitrobenzene (3,5-DCNB) was the most potent nephrotoxicant in renal cortical slices. The current study was designed to explore the nephrotoxicity of 3,5-DCNB and its possible renal biotransformation using isolated renal cortical cells (IRCC) as the in vitro model. Briefly, IRCC (~4.0 million cells/ml, 3 ml) from male Fisher 344 rats were treated with DMSO (vehicle control) or 3,5-DCNB (0.5 or 1.0 mM), and cytotoxicity determined over 90 min by measuring lactate dehydrogenase release. In some experiments, a pretreatment was added before 3,5-DCNB (1.0 mM) followed by 60 min incubations. The pretreatments were antioxidants, cytochrome P450 (CYP) inhibitors, a cyclooxygenase inhibitor, a peroxidase inhibitor or flavin monooxygenase (FMO) inhibitors. All antioxidants and metabolizing enzyme inhibitor pretreatments completely or partially attenuated 3,5-DCNB cytotoxicity. These results suggest that the bioactivation of 3,5-DCNB is complex, as inhibition of enzyme systems as different as CYPs, FMOs, cyclooxygenase and peroxidases can provide some cytoprotection. It can also be concluded that free radicals play a role in 3,5-DCNB nephrotoxicity either via participating in the in vitro renal biotransformation of 3,5-DCNB or via being produced as a consequence of 3,5-DCNB biotransformation. Additional studies are needed to ascertain which pathways are critical for 3,5-DCNB nephrotoxicity. Supported by NIH Grant P20GM103434.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.