Influence of bleeding procedure and some environmental conditions on stress-dependent blood constituents of laboratory rats

Abstract

The influence of experimental conditions on 10 haematological and blood chemical constituents were investigated in male Han:Wistar rats. Significant differences existed between values of haematological and chemical constituents of blood, sampled within 10 s, between 10 and 30, or between 30 and 60 s after decapitation respectively, The leucocyte count decreased quickly but the lactate concentration rose after decapitation. The interindividual coefficient of variance for the majority of the blood constituents was reduced markedly if blood was sampled within 10 s of decapitation. Significant differences in plasma protein and blood lactate concentrations existed between 2 rats kept in one cage, when the first rat was decapitated 20 s before the second one. Plasma protein concentrations differed significantly between rats bled at 9.00 am and 11.00 am. Significant differences in blood glucose and lactate concentrations existed between rats bled on 5 different days within a period of 10 days. Packed cell volume, eosinophilic granulocytes and plasma protein concentration differed significantly between rats kept in a room with a 12:12 light: darkness (LD) cycle and those living in a room with a 2.3:2.3 LD cycle.

Different blood collection methods from rats: A review

“…Bickhardt et al (1983) concluded that variations of haematological and metabolic blood constituents are influenced by the conditions of housing as well as the circumstances of handling for blood sampling. They suggested that in order to avoid "significant" differences between groups which are purely an artefact arising from the condition of bleeding, sampling conditions should be standardised, and animals of different experimental treatment groups should be bled in a strictly random order according to a formal experimental design 6.…”