【Animal Modeling】-Chemical Stimulation Method-induced Pain Model

  (1) Rabbit pain model by potassium ion subcutaneous penetration method

  1. Modeling material animal: rabbit; medicine: saturated potassium chloride solution; device: DC potassium ion pain meter.

  2. Modeling method Hang the rabbit in a cloth bag, let K + subcutaneously penetrate the DC potassium ion pain meter to cause pain. The stimulating pole is a round copper ring with a diameter of 1 cm, which is filled with potassium chloride. Dip the cotton ball into the liquid. Choose the central part of the rabbit's left forelimb as the stimulation site, and make the stimulation electrode contact the skin to fix it. The irrelevant electrode is a thin copper plate measuring 2.5 cm x 2.5 cm containing gauze soaked in salt water and placed on the center and bottom of the rabbit’s left thigh. The current mA value of the contraction of the rabbit's foot after power-on is used as the pain threshold.

  3. Modeling principle Potassium ions can penetrate subcutaneously and cause painful reactions in animals.

  4. Changes after the model is established After charging, it may cause the animal's pain response, that is, the leg contraction response. (2) Rat pain model by potassium ion subcutaneous osmotic pain method

  1. Modeling material animal: rat; drug: saturated potassium chloride solution; device: K + -4 type pain tester.

  2. Modeling method: use K + -4 type pain meter to measure the pain threshold of the rat's tail, fix the stimulation electrode at 1.5 cm from the end of the tail, and make the contact area with the skin about 1 square centimeter. Irrelevant electrodes are fixed with gauze soaked in salt water. At the bottom of the tail, the reaction of the rat's tail is produced from the start of power-up, with a whirlwind and a strong tail flick, a continuous whirlwind and a whole body struggle. The current value is recorded as the movement threshold, the shoe threshold and the callback threshold.

  3. Modeling principle Potassium ions can penetrate subcutaneously and cause pain in animals.

  4. Changes after the model is established After charging, it will cause the animal's pain response, that is, the rat's tail movement response, cyclone, strong tail flick, continuous cyclone and systemic struggle, which is possible.

  (3) Pain model

  1. Modeling materials Animals: mice; drugs: 0.3% acetic acid solution or 0.05% potassium antimony tartrate, 0.02% benzoquinone saturated aqueous solution, 4% sodium chloride solution, 0.02% 2-benzene-1,4 benzoylbenzene Quinone (including 5% ethanol in water), 0.00125% Brazilian kinin; equipment: syringe.

  2. Modeling method Inject one of the following chemical stimulants into the abdominal cavity of mice to cause pain: 0.3% acetic acid solution, 0.2 ml/mouse; 0.05% potassium antimony tartrate, 0.2-0.3 ml/mouse 0.02% benzoquinone saturated aqueous solution 0.25 ml/tablet; 4% sodium chloride solution 0.2 ml/tablet; 0.02% 2-benzene-1,4 benzoyl benzoquinone (including 5% alcohol aqueous solution) 0.2 ml/tablet; 0.00125% brazikinin 0.2 tablet /only.

  3. Modeling principle Injecting chemical stimulants into the abdominal cavity can cause pain in animals.

  4. Changes after modeling After injection, the animal has writhing reactions, such as a concave abdomen (honeycomb), extension of the trunk and hind legs, and bulging of the buttocks. (4) Through bradykinin

  Arterial injection of

  to establish a pain model 1. Modeling materials Animals: rats, males, 250-300 g; drugs: ether, heparin saline (heparin concentration 2500 u/ml), bradykinin saline. 2. Modeling method Gently anesthetize the animal with ether, separate the right carotid artery, and block the proximal end with an arterial clamp. I used a plastic tube (0.5 mm inner diameter) filled with heparin saline. Reverse the direction from the carotid artery to the heart. Insert, ligate, fix, and release the arterial clip, so that the other end of the plastic tube passes through the skin near the cap bone and is guided subcutaneously to the body. Suture the wound. Remove the tip of the cannula, connect it to the IV needle, and firmly insert the end of the needle with a rubber stopper. One hour after anesthesia, the rats were injected with bradykinin saline (0.1-0.5μg/mouse) within 2 seconds.

  3. Modeling principle Arterial injection of bradykinin can cause pain in animals.

  4. Changes after modeling After injection, the rat's right forelimb was bent, the head was bent to the right, hyperactivity (rotational movement, standing or walking on the hind limbs), and occasionally yelling. The above symptoms usually occur within 7-10 seconds after bradykinin administration, and usually last 15-30 seconds after 15 seconds. If the injection interval is 5 minutes, the same reaction may occur within 6 hours. (5) Pain model caused by subcutaneous injection of formaldehyde

  1. Model material animals: male and female mice, 18-22 g; drug: 2.5% formaldehyde solution.

  2. Modeling method Inject the newly prepared 2.5% formaldehyde solution 0.03 ml/ft behind the right hind paw of the animal, observe the waiting time for the mouse to lick the right hind paw and the number of times the right hind paw is licked, I will. The hind legs are within 10 minutes.

  3. Modeling principle Subcutaneous injection of formaldehyde can cause pain in animals.

  4. Changes after modeling After injection, the animal seemed to lick its right hind paw.