Behavioral, clinical and pathological effects of multiple daily intraperitoneal injections on female mice

Pharmacological agents are commonly administered to mice through multiple intraperitoneal (i.p.) injections. The i.p. route of administration is usually considered safe, but questions of animal welfare arise when protocols require that multiple injections be given to the same animal. IACUCs must consider the potential risks associated with multiple i.p. injections in order to determine the maximum number of injections an animal can receive within a study protocol, but there are no published studies of such potential risks. The authors investigated the effects of 30 daily i.p. saline injections on the behavior, body condition, weight, fecal corticosterone levels, hematology and pathology of female adult mice. Results indicate that multiple i.p. injections do not cause any ill effects in mice.