Estimating attrition of Sprague Dawley rats for research involving primary neuronal cultures

Abstract

The use of laboratory animals for biomedical research is strictly regulated to prevent their suffering and inadequate use. While experimentation is in process, attrition usually can increase the number of animals needed to achieve the objectives. Unfortunately, attrition is not commonly reported in literature. In the present study, we worked with primary neuronal cell cultures to establish the first in vitro brain ischemia model in Panama. We report the effects of attrition in the final number of animals. Primary cortical cell cultures were produced from Sprague Dawley rat embryos. Vaginal cytology was used to evaluate oestrus cycle. Pregnant rats had routine evaluation plus clinical/weight follow up. Sample size calculations estimated 26 rats for the study using an attrition rate of 25%. The final number of animals used empirically was 26; however, the measured attrition was 50% (13). These results highlight the importance of calculating attrition for studies requiring laboratory animals, taking in consideration the context and available data from local institutions to allow for the most efficient use of laboratory animals, especially for newly established laboratories in developing countries.