Effect of anesthesia on a whole blood lymphocyte proliferation assay in the rat

Lymphocyte proliferation assays are commonly used to quantify the effects o f immunosuppressive drugs in animal models, but the influence of anesthetic agents on those assays is not well understood. We used a whole blood proli feration assay to compare lymphocyte proliferation in blood drawn from norm al male Lewis rats that were sedated using three common methods. Rats (n = 12) were serially bled from the orbital plexus while anesthetized with diet hyl ether, methoxyflurane, or carbon dioxide. Before the beginning of the a nesthetic trials, a random subset of the rats (n = 6) was bled via the jugu lar vein using only manual restraint to provide a baseline central group. A comparison of the lymphocyte proliferation results obtained under these fo ur conditions (manual restraint, diethyl ether, methoxyflurane, or CO2) sho wed no significant differences. The only hematological variation seen was a n elevation of the number of circulating lymphocytes when ether was used. W e conclude that there is no justification for withholding sedation when ble eding rats for this type of lymphocyte proliferation. Furthermore, when con sidering the use of one of the agents examined in this study, the method ca n be chosen based on factors other than potential adverse effects on the as say results.