A comparison of two methods of bleeding rats: the venous plexus of the eye versus the vena sublingualis.

Of paramount importance to most toxicological studies in rats is the evaluation of hematological and clinical chemistry parameters. Currently, the principle bleeding method utilizes the venous plexus of the eye. This procedure has no detrimental effect on the general health of the animal and yields a sufficient quantity of blood, but has the potential disadvantage of damaging the eye. To avoid this disadvantage, a method was developed which is simple to perform, yields a sufficient quantity of blood and leaves the eye unimpaired. Samples are taken from the vena sublingualis. In order to compare the two methods, a study was initiated to determine the effect on body weight and food consumption as well as to compare hematological and serum chemistry parameters. The results showed that drawing blood from the vena sublingualis did not affect body weight or food consumption, and no significant differences were found in the hematological or serum chemistry values obtained by either method.