Effects of Isoflurane Anesthesia on C57BL/6J Pups after Cervical Dislocation of Dams.

Inhalant anesthesia is routinely used for cesarian section in many animal species, allowing the safe delivery of neonates and smooth recovery of dams. However, in mice, inhalant anesthesia in cesarean section may be avoided due to fear of negative health effects on retrieved pups. This study compared the effects of isoflurane anesthesia on pups after cervical dislocation of conscious and anesthetized dams. Time-mated C57BL/6J dams were either anesthetized with 5% isoflurane or were conscious during cervical dislocation. Rederived pups were fostered to Swiss Webster dams and weaned at 21 d. Weights of litters were recorded at birth, and individual pup weights were recorded at weaning. We found no significant difference between the two treatment groups in pup survival until weaning. We also found no significant difference when comparing the average weaning weights of all the male pups to that of all the female. Female pups from isoflurane-treated dams had significantly higher weaning weights than did those from unanesthetized dams; however, the weights of male pups from the two groups were not different at weaning. This study found no immediate negative effects of using isoflurane anesthesia prior to cervical dislocation of C57BL/6J pregnant dams for the purpose of rederivation. Isoflurane can be used for cervical dislocation of pregnant C57BL/6J dams without affecting pup survival.

Strength and Sterility of Stock and Diluted Carprofen Over Time.

Carprofen, a nonsteroidal antiinflammatory drug, is a commonly used analgesic for laboratory animals. The manufacturer labeling indicates the stock bottle may be stored and used for up to 28 d under refrigeration. However, institutional guidelines may vary in how long diluted carprofen solutions can be stored before they must be discarded. When administered to laboratory rodents, small volumes of the stock solution are diluted to provide accurate dosing and ease of administration. Because carprofen is formulated for use in companion animals (for example, dogs) and comes in larger volume multidose vials, the majority of carprofen at our institution is discarded before it can be used. In this study, we evaluated the amount of target ingredient present (strength), sterility, and endotoxin levels of both stock and diluted carprofen when stored in a variety of containers and at multiple temperature settings for up to 180 d, mimicking facets of typical use in laboratory animal research and medicine. We demonstrated that when refrigerated and stored in sterile vials, stock and diluted carprofen can be kept and used for up to 180 d while retaining strength and sterility. For short-term use, diluted carprofen can also be stored for up to 60 d at room temperature in conical tubes. These results will help establish scientifically justified storage conditions for carprofen to ensure that these agents remain appropriately potent and sterile for therapeutic use in laboratory animals.