Mouse Surgery Protocol ( Click to Download )

A. Dimethylbenzanthracene (DMBA, Calbiochem) will be dissolved in cottonseed oil to yield a 0.25% (w/v/) solution. A dose of 0.2 ml will be administered by gastric intubation once each week for 3 consecutive weeks starting when the mice are 8 weeks old. DMBA is made up fresh and just before use. The carcinogen in solution is light sensitive so the flask containing the solution is wrapped in aluminum foil. We ensure safe handling by using carcinogen dedicated balance, flask and spatula. Wear gloves and administer carcinogen to mice in a hood and use disposable diapers or coverings on any surface area where carcinogen is placed or used. The room should be low light or reflected light. The flask, spatula and feeding needle are rinsed in acetone and the solution put in a dedicated bottle exposed to light. Eventually the filled bottle is collected by environmental safety and the material appropriately disposed. The half life of DMBA in oil solution is approximately 30 minutes when exposed to normal ambient laboratory lighting conditions. The bottle containing the powdered carcinogen is kept in a locked cabinet. The cages containing the mice receiving carcinogen are handled specially for four weeks following carcinogen feeding. All feces, cage shavings and uneaten food are collected and incinerated at >1800 degrees. The carcinogen shows up in feces and urine for up to 10 days after treatment, so we build in a safety factor of an additional 20 days.