动物造模,猴脊髓半横断损伤模型 z-bo 2022-02-02 480

       1. The purpose of the experiment

　　 Every year, many Chinese patients suffer from severe sequelae, such as paralysis caused by SCI. How to regenerate nerve cells and nerve fibers after spinal cord injury and how much function is restored are very important issues. In recent years, people have conducted a large number of experimental studies to explore the mechanism of repairing spinal cord injury, but so far, the assessment of spinal cord injury in various animal experiments has been very different, and there is no optimal spinal cord injury. model. In order to improve the application value of the experiment, the author established an adult rhesus monkey spinal cord hemisection injury model with non-human primate macaques as experimental animals to repair and repair the spinal cord injury for future clinical applications. The regeneration mechanism has been studied and some foundations have been provided.

　　二. Experimental materials and methods

1. Experimental equipment YXQ.SG41.280A electric pressure steam sterilizer; HT-200 miniature electronic balance; 8KFG-01 electric heating constant temperature blast drying oven; electric distilled water meter; 20μl, 100μl, 200μl, 1000μl adjustable micro sampling gun ; 80°C low-temperature refrigerator; -20°C BD-618 horizontal freezer; AMBZ-5-P laboratory-grade ultrapure water machine; surgical instruments: Kerrison forceps, ophthalmic scissors, dissecting scissors. , Mosquito forceps, toothed forceps, toothless forceps.

2. Experimental materials Eight adult rhesus monkeys, male and female, about 2 years old, weighing 3.5-4.5 kg (provided by the Experimental Animal Center of Kunming Medical University), were randomly divided into two groups: sham operation group and spinal cord hemisection group. 4 in each group.

　　3. Specific experimental methods and operating procedures

　　 (1) Establish a spinal cord hemisection model: ketamine (50 mg/kg) and diazepa (1.5 mg/kg) combined with intramuscular injection of anesthetized animals, prone for fixation, and regular skin preparations, disinfection and towels. Make a central incision about 5 cm in length around the T10 spinous process, cut the back skin, subcutaneous tissue, pectoralis major and back fascia layer by layer, cut the spinous process appendages of the paraspine muscles, and use a corn cob to peel Device. The process of stripping the lower vertebrae from the auxiliary muscles to the joints is filled with dry gauze to stop bleeding. The automatic retractor contracts the paraspinal muscles, cleans the remaining soft tissues beside the vertebral arch and spinous process, cuts the T10 supraspinous ligament and interspinous ligament, cuts the Tm spinous process, and removes the yellow ligament. Cut and expose the spinal cord with Kerrison forceps and open the vertebral arch.

　　 Remove the dura mater and arachnoid membrane. During the operation, cerebrospinal fluid drainage and normal spinal cord pulsation can be seen. The spinal cord is characterized by posterior median blood vessels. The sharp sharp blade is quickly withdrawn from the posteromedial fissure of the spinal cord to the left side of the spinal cord and part of the spinal cord tissue. Similarly, in the sham operation group, the left 1mm spinal cord was incised sequentially, the dura mater was sutured intermittently after the operation, the muscle layer and skin were sutured in layers, and the pedicle was cut. However, do not open the dura mater. After the operation, 800,000 units of penicillin sodium was given as an intravenous infusion to prevent infection, strengthen control and prevent complications.

　　(2) Behavior observation: Observe the voluntary movement, muscle strength and muscle tension of the hind limbs at 24 hours, 1 month, 2 months and 3 months after surgery. According to Tarlovscale, the muscle strength of hind limbs after spinal cord injury was evaluated.

　　 3. Experimental results

　　Behavioral observation: 24 hours after injury in the sham operation group, the muscle strength of the hind limbs in the bi-anatomical spinal cord group was level 3, and the muscle strength of the left hind limb in the semi-anatomical spinal cord group was level 0, with decreased muscle tension. It is manifested as delayed paralysis, and the right muscle strength is level 3. Three days after the injury, the hind limbs of the sham operation group returned to normal. Five to seven days after the injury, the muscle strength of the other hind leg returned to normal and was able to support the weight. On the fourteenth day after the injury, the muscle mass of the half-amputation hindlimb was reduced, showing spastic paralysis of the left hind limb. One month after the injury, the muscle strength of the hind limbs on the same side of the spinal cord was level 2; within 3 months after the injury, the muscle strength of the left two hind limbs was level 3. , The rest are level 4, with active grip and partial load.

  No 4. Result analysis

　　 In this study, the functional changes of hind limbs were observed by cutting the left T11 spinal cord of adult rhesus monkeys. After the operation, the motor function of the left hind limb may be completely lost and partially recovered within 14 days. A few months later, the lateral force was injured. In the case of active grip and partial load, the score is highest. The cortical somatosensory evoked potential (CSEP) results of unilateral spinal cord transection showed that the P1 latency was prolonged and the P1-N1 amplitude was significantly reduced, indicating that the sensory conduction pathway was damaged. I will. Meng Xiaomei et al. (2002) showed that the changes of somatosensory evoked potentials after spinal cord hemisection in adult monkeys are closely related to the motor function of the hind limbs, which indicates an indirect and objective indicator of the motor function of hind limbs after spinal cord injury. The results show. The control of normal human movement is reflected in the subtle and dynamic balance between the various levels of the nervous system. After severe or complete spinal cord injury, many animals can reproduce hind limb movement in the lower part of the spinal cord injury. After the injury, the spinal cord gradually gains partial motor control. ability. These studies indicate that the plasticity of motor control may be caused by the remodeling of the endogenous neuron network in the spinal cord below the injury site. In addition, many scholars believe that the semi-anatomical contralateral spine bud is also an important factor in promoting neuroplasticity. In other words, they have a certain ability to repair themselves after spinal cord injury. The author used the posterior approach acute spinal cord semi-incision model, compared the semi-incision side with the contralateral side, selected human rhesus monkeys as experimental animals, and performed a sharp laminar incision to reduce intraoperative injury. This method is used to observe the changes in the nerve function of the hind limbs after the spinal cord is compressed, and establish a stable and reproducible non-human primate rhesus macaque spinal cord hemisection model. The required equipment is simple, easy to operate, reproducible and has good controllability. Through motor scores, somatosensory evoked potentials, and histomorphological studies, it is confirmed from the behavior that after experimental spinal dysfunction in monkeys, neurological function may be spontaneously restored. This limited plasticity of spinal cord function after injury may lead to protective body self-rescue, and the exact response mechanism needs further research.