Techniques of blood collection in laboratory animals


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blood collection techniques from laboratory animals

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Techniques of blood collection in laboratory animals

  1. 1. TECHNIQUES OF BLOOD COLLECTION IN LABORATORY ANIMALS <ul><li>INTRODUCTION </li></ul><ul><li>To study the effects of test drugs. </li></ul><ul><li>Hormones, substrates or blood cells. </li></ul><ul><li>Terminal and non-terminal blood collection techniques. </li></ul><ul><li>Death of the animal (terminal experiment). </li></ul><ul><li>Terminal blood collection under anesthesia. </li></ul><ul><li>Non-terminal blood collection-> from conscious animal. </li></ul>
  2. 2. ASPECTS OF ANIMAL WELFARE <ul><li>Minimizing pain & distress. </li></ul><ul><li>Humanitarian reasons. </li></ul><ul><li>Good scientific practice. </li></ul><ul><li>Physiological changes associated with stress. </li></ul><ul><li>e.g. :- increases in the blood levels of catecholamines, prolactin & glucocorticosteriods can influence certain metabolic parameters, such as glucose, as well as the counts of erythrocytes, white cells, & packed cell volume. </li></ul>
  3. 3. TOTAL BLOOD VOLUME <ul><li>Depends on species, sex, age & health ass well as nutritional conditions. </li></ul><ul><li>Blood volume less in older, obese when compared to normal. </li></ul><ul><li>Total circulating blood volume is in the range of 55-70 ml/kg body weight. </li></ul>
  4. 4. TERMINAL BLOOD COLLECTION <ul><li>Exsanguination as a single process. </li></ul><ul><li>Multiple blood sampling during terminal experiments by physical stunning or general anesthesia. </li></ul><ul><li>Types :- </li></ul><ul><li>1) Blood withdrawal from the V.cava caudalis or the aorta after laparactomy-> as much blood as possible should be removed in a sterile manner . </li></ul>
  5. 5. <ul><li>2) Exsanguination after decapitation, incision of the jugular vein or carotid artery or techniques in the slaughterhouse-> Non-sterile collection . </li></ul><ul><li>3) Retro-orbital bleeding-> In mice, hamsters & rats-> which can also be method of exsanguination. </li></ul>
  6. 6. NON-TERMINAL BLOOD COLLECTION (From conscious animal) <ul><li>Not to with draw too much of blood. </li></ul><ul><li>False results. </li></ul><ul><li>Reduced total blood volume in animal. </li></ul><ul><li>Reduced hemoglobin content & reduced oxygen transport capacity. </li></ul><ul><li>Fall in blood pressure. </li></ul><ul><li>Increased conc. of stress related hormones. </li></ul><ul><li>Necrosis of the gastric mucosa. </li></ul><ul><li>Individual animal should not be endangered by removal of too large volume & too frequent collection of blood. E.g. :- mice, rats or hamsters are used. </li></ul>
  7. 7. SINGLE BLOOD REMOVAL <ul><li>Removal of 15 to 20%-> Accompanied by side effects such as fall in c.o or b.p. </li></ul><ul><li>Haemorrhagic shock-> By the withdrawal of 30-40% of total blood volume. Loss of 40% causes mortality. </li></ul><ul><li>3-4 weeks gap between every withdrawal. </li></ul><ul><li>Hypovolaemic shock symptoms-> fast pulse, pale mucous membranes, hyperventilation, normal body temp including cold skin & extremities. </li></ul>
  8. 8. MULTIPLE BLOOD REMOVAL <ul><li>Not exceeding 1% of total blood volume every 24 hr (0.6 ml/kg/d). </li></ul><ul><li>Symptoms of anemia-> pale mucous memb of conjunctiva or inside the mouth, intolerance to exercise & an increased respiratory rate. </li></ul><ul><li>Anemia can be easily detected by PCV, ECR, Hg. </li></ul><ul><li>Anemia treated with iron & vitamin B 12. </li></ul>
  9. 9. TECHNICAL ASPECTS OF BLOOD REMOVAL <ul><li>0.1 ml -> Tip of the tail. </li></ul><ul><li>Fresh capillary blood. </li></ul><ul><li>E.g.:- Blood glucose or total radioactivity after the administration of radio labeled drugs. </li></ul><ul><li>Guinea pig-> cardiac puncture under general anesthesia. </li></ul><ul><li>In large animals blood collection by -> superficial vein. </li></ul><ul><li>Locate the vessel accurately before insertion of needle or catheter. </li></ul>
  10. 10. <ul><li>Bore of the needle should be as large as possible to ensure rapid blood withdrawal. </li></ul><ul><li>Continuous pressure should be applied immediately and maintained for 30 sec. </li></ul><ul><li>Monitored 15mins later. </li></ul>
  11. 11. PERMANENT VENOUS CANNULATION <ul><li>By chronic cannulation. </li></ul><ul><li>Particularly in rats. </li></ul><ul><li>A few days after the implantation of catheters, hormone levels are normal. </li></ul><ul><li>Housed alone. </li></ul><ul><li>Tethering restricts normal movements such as lying on the back and rolling over. </li></ul><ul><li>At the time of experiments longer catheter is attached. </li></ul>
  12. 12. SHORT -TERM CANNULATION <ul><li>A butterfly needle. </li></ul><ul><li>Clotting can be prevented by repeatedly filling the catheter with saline containing heparin. </li></ul>
  13. 13. RETRO-ORBITAL BLEEDING <ul><li>Orbital puncture. </li></ul><ul><li>Orbital venous plexus. </li></ul><ul><li>Tail less animals e.g. :- hamsters also rats & mice. </li></ul><ul><li>Pasteur pipettes, micropipettes or micro capillary tubes. </li></ul><ul><li>Rotating movements through the conjunctiva laterally, dorsally or medially of the eye to the back wall of the orbit. </li></ul><ul><li>Retrorbital haematoma with subsequent pressure on the eye cannot be excluded </li></ul>
  14. 14. CARDIAC PUNCTURE <ul><li>Performed in guinea pig, gerbils & hamsters. </li></ul><ul><li>Difficult to collect blood by alternative methods except retro-orbital bleeding. </li></ul><ul><li>Performed under general anesthesia. </li></ul>
  15. 15. THANK YOU