Experiments on the role of reduced plasma colloid osmotic pressure in the development of edema
Experiments on the role of reduced plasma colloid osmotic pressure in the development of edema
This experiment is from the official website of Zhejiang University Fine Courses
Operation method
Experiments on the role of reduced plasma colloid osmotic pressure in the development of edema
Materials and Instruments
Toad Heparin injection Ren's solution 60g L (6g dl) medium molecule dextrose. Frog plate Frog needle Coarse scissors Ophthalmic scissors Dentate forceps Ophthalmic forceps Syringe and needle Fine plastic tubing Tension transducer. Frog lower limb perfusion device Beaker Peg Frog heart clip Move 1. Preparation of specimens of isolated lower limbs of toads Caveat 1. The toad should be big, otherwise the dorsal aorta is too thin and it is not easy to intubate. 2. Avoid air bubbles in the thin plastic tube to prevent poor perfusion. 3. Don't make the blood vessels twisted, after twisting the perfusion is not smooth or stop. 4. Keep the distance between the liquid level of the perfusate and the cannula of the specimen between 20 and 30 centimeters. For more product details, please visit Aladdin Scientific website.
(1) Take a larger toad, destroy its cerebral spinal cord with a probe, and fix the limbs with pins from the abdomen upward.
(2) Cut open the abdominal skin, incise the abdominal wall along the center of the abdomen, and inject 10g/L (1g/dl) heparin 0.5ml into the abdominal vein.
(3) Widen the abdominal wall incision and cut the sternum upward and downward until the pubic symphysis. The cloaca of the toad is cut, and all abdominal organs are pushed cephalad to expose the posterior peritoneum (Fig. 10-7-1A).
(4) The posterior peritoneum is cut at the outer edge of the left kidney to reveal the dorsal aorta (Fig. 10-7-1B)
(5) Two thin threads are threaded under the dorsal aorta, the upper (proximal cephalic) thread is pulled taut, and a small incision is carefully cut just below the thread with ophthalmic scissors (relaxing the taut threads slightly, the incision is cut when blood flows from the small opening). Insert, ligate, and secure the thin plastic tube that has been drained of gas through the small opening toward the lower extremity. (Note that the cut should be 0.8 to 1 cm above the bifurcation of the iliac artery, so that the tube is not inserted too low, and only one side of the lower limb can be perfused (Figure 10-7-1C).
(6) Use coarse scissors to transect the trunk above the cannula, taking care not to twist the cannula (Fig. 10-7-1D).
(7) Slowly push 2 to 4 ml of Ren's solution into the thin plastic tube with a syringe. flush the blood from the vessels of the second lower extremity.
2. Connecting the lower limb perfusion specimen and perfusion device
Clamp the broken end of the vertebrae of the lower limb specimen with a frog heart clip. The upper end of the frog heart clip is knotted with a thin line, and the whole specimen (together with a thin plastic tube inserted into the blood vessel) is suspended on the tension transducer.
3. Perfusion of dextrose anhydride solution
(1) to the perfusion device at the highest point of the graduated container poured into Ren's liquid, open the spiral clamp so that Ren's liquid through the Murphy's dropper, slowly open the side tube of the A spring clamp to adjust the amount of air, clamping the spring clamp, Ren's liquid drop by drop into the two posterior limbs, in the proof that the perfusion system is fluent and stable (should not be too long) open the B spring clamp, so that the graduated container of liquid will be part of the discharge. Close the screw clamp C.
(2) Pour a quantitative 60 g/L (6 g/dl) of a medium molecule dextran solution into the graduated container.
(3) Slowly open screw clamp C to allow the dextrose anhydride solution to enter both lower extremities through the thin plastic tubing while the tension transducer is turned on and the curve is traced intermittently or continuously as a baseline.
(4) After 10 minutes of perfusion, open spring clip B to drain the dextrose solution, replace it with Ren's solution, and continue to perfuse for 10 minutes, the perfusion rate should be consistent with that of dextrose, and continue to open the tension transducer intermittently or continuously to trace the curve.
(5) Organize and analyze the experimental results