Haematological, immunological and endocrinological aspects of chronic high frequency blood sampling in rats with replacement by fresh or preserved donor blood

Abstract

Haematological, immunological and endocrinological aspects of blood transfusions with either freshly collected or preserved donor blood were investigated in chronically cannulated unrestrained rats. Three anticoagulant preservatives were tested: citrate, citrate-dextrose and citrate-phosphate-dextrose-adenine (CPDA-1). Prolactin was used as an indicator of stress in endocrine studies. The repeated collection of 4 ml blood at 2-week intervals did not affect normal blood composition. Whole blood of rats could be stored in citrate, citrate-dextrose or CPDA-1 for 8, 22 or 35 days, respectively. Blood transfusions with fresh or preserved donor blood of F1 (R X U) rats did not affect normal blood composition nor did it induce immunological responses in F1 rats. Frequent blood sampling for several hours at highest rates of 1 sample/min did not affect prolactin secretion when blood volume reduction was replaced by blood transfusions with fresh donor blood. However, compensation with preserved blood affected prolactin secretion significantly. Blood transfusions did not affect health, behaviour, cyclicity or pseudopregnancy. The application of blood transfusion in chronically cannulated rats appeared to be quite simple. Its advantages are the possibility of following individual secretion patterns of blood-bound substances, the repeated use of animals and the reduction of the number of animals.

Electrophysiological Evidence for a Sex Difference in Neural Regulation of Prolactin Secretion in Rats

“…Although the usual practices o f animal handling, surgery, anesthesia and blood sampling may easily induce stress, we recently reported that blood sampling/transfusion under chronic conditions with freely moving rats can be performed without stress [40,41). In the present study we added a new element, the chronic implantation o f metal electrodes into the hypothalamus.…”

“…The blood volume reduction was compensated by blood transfusions with freshly collected donor blood every time a total o f 1 ml blood had been withdrawn. This blood sampling procedure appeared to be free o f stress [40,41].…”

Electrophysiological Evidence for a Key Control Function of the Medial Preoptic Area in the Regulation of Prolactin Secretion in Cycling, Pregnant and Lactating Rats

“…Rats were fitted chronically with stimulation electrodes and a blood sampling catheter as described previously [41,42,44,45]. Electrodes were made of stainless steel (type 304) wire of 0.2 mm diameter and insulated with epoxylite (EPR-4, Clark Electromedical Instruments, UK) except for 0.4 mm at the tip.…”

“…Blood volume reduction was compensated for by blood transfu sions with freshly collected donor blood every time a total of I ml of blood had been withdrawn. This experimental approach appeared to be free o f stress [41,42,44,45].…”

“…As such, the female rat displays unique patterns of Prl secretion, dependent upon the reproductive state. Prl secretion in cycling rats is char acterised by a surge during the afternoon and early night of proestrus and a surge on the afternoon of estrus [3, 6, 27, 31, 32,[43][44][45]. Pregnant rats secrete twice daily a surge of Prl for ap proximately 10 days, a nocturnal surge in the early morning hours and a diurnal surge in the late afternoon [4,35,40].…”