Biomaterial Database

The measurement of DNA strand breaks in rat colonic mucosa by fluorometric analysis of DNA unwinding. 1991

A J Percy, and J K Chipman

School of Biochemistry, University of Birmingham, U.K.

We describe the detection of DNA strand breaks in the rat colonic mucosa (in vivo and in vitro) by fluorometric analysis of DNA unwinding. DNA strand breaks were detected, in a dose-dependent manner, 2 h following an intracaecal dose of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG, 5-100 mg/kg). Levels of double-stranded DNA in the colonic mucosa of control animals, after 60 min unwinding time, were 62.8 +/- 3.4% (n = 6) and were significantly reduced at 5 mg/kg to 52.1 +/- 1.9% (n = 3). DNA strand breaks were also detected in isolated rat colonic mucosal cells following 15 min treatment with MNNG (0.1-1 mM) in vitro. The percentage of double-stranded DNA, after 60 min unwinding time, was significantly reduced (13.6 +/- 5.4%, n = 3) from control levels following treatment with 0.1 mM. A post-treatment incubation (30 min) of cells treated at a MNNG concentration of 0.25 mM resulted in 78.2 +/- 24.0% (n = 3) of these lesions being repaired.

UI	MeSH Term	Description	Entries
D007413	Intestinal Mucosa	Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.	Intestinal Epithelium,Intestinal Glands,Epithelium, Intestinal,Gland, Intestinal,Glands, Intestinal,Intestinal Gland,Mucosa, Intestinal
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008297	Male		Males
D008769	Methylnitronitrosoguanidine	A nitrosoguanidine derivative with potent mutagenic and carcinogenic properties.	Methylnitrosonitroguanidine,Nitrosomethylnitroguanidine,Nitrosonitromethylguanidine,MNNG,N-Methyl-N'-nitro-N-nitrosoguanidine,N Methyl N' nitro N nitrosoguanidine
D009690	Nucleic Acid Conformation	The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.	DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D003106	Colon	The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.	Appendix Epiploica,Taenia Coli,Omental Appendices,Omental Appendix,Appendices, Omental,Appendix, Omental
D004249	DNA Damage	Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.	DNA Injury,DNA Lesion,DNA Lesions,Genotoxic Stress,Stress, Genotoxic,Injury, DNA,DNA Injuries
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D005470	Fluorometry	An analytical method for detecting and measuring FLUORESCENCE in compounds or targets such as cells, proteins, or nucleotides, or targets previously labeled with FLUORESCENCE AGENTS.	Fluorimetry,Fluorometric Analysis,Analysis, Fluorometric