Enrichment with wood blocks does not affect toxicity assessment in an exploratory toxicology model using Sprague-Dawley rats.
Environmental enrichment in rodents may improve animal well-being but can affect neurologic development, immune system function, and aging. We tested the hypothesis that wood block enrichment affects the interpretation of traditional and transcriptomic endpoints in an exploratory toxicology testing model using a well-characterized reference compound, cyclophosphamide. ANOVA was performed to distinguish effects of wood block enrichment separate from effects of 40 mg/kg cyclophosphamide treatment. Biologically relevant and statistically significant effects of wood block enrichment occurred only for body weight gain. ANOVA demonstrated the expected effects of cyclophosphamide on food consumption, spleen weight, and hematology. According to transcriptomic endpoints, cyclophosphamide induced fewer changes in gene expression in liver than in spleen. Splenic transcriptomic pathways affected by cyclophosphamide included: iron hemostasis; vascular tissue angiotensin system; hepatic stellate cell activation and fibrosis; complement activation; TGFβ-induced hypertrophy and fibrosis; monocytes, macrophages, and atherosclerosis; and platelet activation. Changes in these pathways due to cyclophosphamide treatment were consistent with bone marrow toxicity regardless of enrichment. In a second study, neither enrichment nor type of cage flooring altered body weight or food consumption over a 28-d period after the first week. In conclusion, wood block enrichment did not interfere with a typical exploratory toxicology study; the effects of ingested wood on drug level kinetics may require further consideration.
Cellular, Molecular, and Exploratory Toxicology, DSS, AbbVie, North Chicago, Illinois, USA.
Amy C
AC
Ditewig
Office of Animal Welfare and Compliance, DSS, AbbVie, North Chicago, Illinois, USA.
Natalie A
NA
Bratcher
Toxicology, DSS, AbbVie, North Chicago, Illinois, USA.
Donna R
DR
Davila
630 East Golf Road, Libertyville, Illinois, USA.
Brian D
BD
Dayton
Comparative Medicine, DSS, AbbVie, North Chicago, Illinois, USA.
Paige
P
Ebert
Cellular, Molecular, and Exploratory Toxicology, DSS, AbbVie, North Chicago, Illinois, USA.
Philippe
P
Lesuisse
Cellular, Molecular, and Exploratory Toxicology, DSS, AbbVie, North Chicago, Illinois, USA.
Michael J
MJ
Liguori
Exploratory Kinetics, DSS, AbbVie, North Chicago, Illinois, USA.
Jill M
JM
Wetter
Exploratory Statistics, DSS, AbbVie, North Chicago, Illinois, USA.
Hyuna
H
Yang
Cellular, Molecular, and Exploratory Toxicology, DSS, AbbVie, North Chicago, Illinois, USA. wayne.buck@AbbVie.com.
Wayne R
WR
Buck
D000284:Administration, Oral; D000818:Animals; D000830:Animals, Laboratory; D018906:Antineoplastic Agents, Alkylating / Q000008:administration & dosage*; D001835:Body Weight / Q000187:drug effects; D003520:Cyclophosphamide / Q000008:administration & dosage*; D008099:Liver / Q000187:drug effects; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014116:Toxicology / Q000379:methods*; D014934:Wood
D018906:Antineoplastic Agents, Alkylating; D003520:Cyclophosphamide