Related Experiment Video
Updated: Jun 5, 2026
Assessing Hepatic Metabolic Changes During Progressive Colonization of Germ-free Mouse by 1H NMR Spectroscopy
Published on: December 15, 2011
Toxicological characterization of N-methyl-N-nitrosourea-induced cataract in rats by LC/MS-based metabonomic analysis
Yuko Miyazono1, Kazuo Harada, Koji Sugiyama
1Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
Abstract:
Cataract is one of the most serious drug-induced side effects that can terminate the development of drug candidates, and pharmaceutical companies consider it important to evaluate cataract-inducing potential in the early phases. Metabonomics is expected to be a powerful approach for the safety evaluation of drug candidates. In this study, we conducted a toxicological characterization of N-methyl-N-nitrosourea (MNU)-induced cataract in rats by LC/MS-based metabonomic analysis. MNU was intraperitoneally administered once to 15-day old rats at 70 mg kg(-1) . After that, animals were kept for 3 weeks waiting for cataract formation. Lens samples for metabonomic analysis were collected on 7, 14 and 21 days after MNU administration. Comprehensive analyses of lens metabolites were conducted using an LC/MS system, and multivariate data for each sample were compared by principal component analysis (PCA) to find any changes in lens metabolites. Lens opacity was confirmed by ophthalmoscopy 14 days after dosing, and even by gross observation 21 days after dosing. PCA of the lens samples for the control and MNU-treated groups revealed that the metabolite profiles of lens differed from each other, and several lens metabolites, such as lots of α-amino acids and gluthathione, decreased after MNU treatment. In conclusion, metabonomic analysis enabled us to identify new marker candidates for cataract and provided a better understanding of the mechanism related to MNU-induced cataract. It was considered that metabonomics is a useful approach for the characterization of drug-induced toxicity.
Insights
Metabonomics effectively identified changes in lens metabolites, like decreased alpha-amino acids and glutathione, following N-methyl-N-nitrosourea (MNU) administration. This approach aids in understanding drug-induced cataract mechanisms and evaluating drug candidate safety.
Area of Science:
- Toxicology
- Pharmacology
- Biochemistry
Background:
- Cataract is a significant drug-induced side effect, necessitating early evaluation of drug candidates.
- Metabonomics offers a promising approach for assessing drug safety and toxicity.
- N-methyl-N-nitrosourea (MNU) is a known agent for inducing cataracts in experimental models.
Purpose of the Study:
- To characterize the toxicological effects of MNU-induced cataract using liquid chromatography/mass spectrometry (LC/MS)-based metabonomics.
- To identify potential metabonomic markers for drug-induced cataract.
- To elucidate the underlying mechanisms of MNU-induced cataract formation.
Main Methods:
- MNU was administered to 15-day-old rats, and lens samples were collected at 7, 14, and 21 days post-administration.
- LC/MS-based metabonomic analysis was performed on lens tissue.
- Principal component analysis (PCA) was used to analyze and compare metabolite profiles between control and MNU-treated groups.
Main Results:
- Lens opacity was confirmed by ophthalmoscopy and gross observation.
- PCA revealed distinct metabolite profiles between control and MNU-treated rat lenses.
- Significant decreases in alpha-amino acids and glutathione were observed in MNU-treated lenses.
Conclusions:
- Metabonomic analysis successfully identified changes in lens metabolites associated with MNU-induced cataract.
- This study highlights metabonomics as a valuable tool for characterizing drug-induced toxicity and identifying novel biomarker candidates.
- The findings provide insights into the biochemical mechanisms underlying MNU-induced cataract.
