On the day of the blood sampling, place the rat in the cage at 8:00 AM.Weigh the food and water and place them in the cage. Define successful blood sampling based on the following criteria. Have a blinded researcher record the rat's weight, food consumption, and water intake daily at 8:00 AM.Next, gently stroke the rat's back skin and pinch its neck repeatedly to help the rat relax.
Using the non-dominant hand's thumb and index finger, grip and lift the rat's neck skin. Using the remaining three fingers and the palm of the non-dominant hand, secure the rat's back skin, and with the help of the dominant hand, immobilize its front limbs. Using the non-dominant hand's index finger, gently push down on the rat's head skin.
Rotate the shoulder joint outwardly with the other fingers along the palm while the dominant hand fully extends the shoulder joint. Grip the rat firmly with the non-dominant hand to align its head and body in a straight line. Locate the clavicle with the dominant hand and confirm the injection site.
Disinfect the site with alcohol, then flush the syringe with sodium heparin. Hold the syringe parallel to the rat's body and the dominant hand with the needle tip facing upwards and the syringe scale toward the experimenter. Insert the needle 0.5 centimeters below the clavicle notch.
Gently withdraw the syringe to create negative pressure, collecting 0.1 to 1 milliliters of blood at a constant speed. Apply a cotton swab for hemostasis and return the rat to its cage. Average blood collection times for groups A and B were similar over 96 hours.
Blood collection success rates were 93.8%for group A and 95.8%for group B, with no significant difference. Group A had a shorter average blood collection time on the second day compared to the fourth day. The number of attempts for successful blood collection averaged 1.21 for group A and 1.17 for group B.More attempts and longer puncture times indicated higher failure rates.
Both groups showed steady weight gain over four days. Water and food intake remained relatively constant among rats of the same sex.
