动物造模,药效评价,脑血管痉挛 z-bio 2024-08-21 347

　　(1) The replication method used to create a DCV model in rats after subarachnoid hemorrhage by inserting a catheter through the frontal subarachnoid space and injecting blood twice directly into the Willis circle of the cerebral artery.

　　Healthy rats weighing 200-250g, regardless of gender, were anesthetized by intraperitoneal injection of chloral hydrate (at a dose of 350-400 mg/kg body weight) or pentobarbital sodium (at a dose of 50-60 mg/kg body weight). The hair on the top of the head was shaved, and the skin in the surgical area was disinfected. Cut the skin along the midline of the head and top, bluntly separate the muscles and periosteum. Use an electric dental drill to drill a hole into the meninges 5mm in front of the anterior fontanelle and 3mm along the midline. This bone hole is located at the junction of the anterior cranial fossa and the frontal pole. Appropriately expand the bone foramen, carefully puncture the meninges under a surgical microscope, and when clear cerebrospinal fluid flows out, point the tip of the PC-10 plastic tube towards the midpoint of the binaural line, tightly adhere to the subarachnoid space of the anterior skull base, and deliver it to a depth of 8-10mm (measured anatomically, this length of the catheter tip is located in the anterior part of the Willis circle). Connect the syringe to withdraw clear cerebrospinal fluid without blood, indicating successful puncture. Seal the bone wound with bone wax, suture the muscles, and fix the puncture tube. Drill a bone hole on the left or right side 3mm behind the anterior fontanelle and 3mm beside the midline, puncture the meninges, and insert measuring electrodes into the cortex (1mm depth) for measuring local cerebral blood flow (rCBF).

　　Cut off the tail and take 150 μ l of autologous blood, slowly inject it into the subarachnoid space through a PC-10 tube, seal the plastic tube and suture the skin. After 24 hours of anesthesia fixation, cut open the plastic tube and inject 100 μ l of autologous blood again. Physiologically administered 6 hours after the last blood injection

　　Saline infusion, fixed with 4% paraformaldehyde infusion, first fast and then slow, decapitated and brain removed for gross and morphological observation. Cerebral angiography can also be performed 6 hours after the last blood injection to observe the overall cerebral vasospasm. Method: After anesthesia, the skin of the neck was cut open, the common carotid artery was separated, and a catheter was inserted into the skull base through the internal carotid artery. 1ml of 60% meglumine diatrizoate was injected for whole brain imaging.

　　(2) The rCBF measurement of the model features a significant decrease in local blood flow. A large amount of blood can be observed to accumulate in the Willis circle of the cerebral artery. The anterior middle artery and basilar artery of the brain are all enveloped by old blood clots, and there are remnants of old blood clots at the base of the anterior cranial fossa, sella turcica, and posterior cranial fossa. Observation of microvascular morphology shows a reduction in microvascular diameter. Image analysis shows a significant decrease in total vascular area, number of vessels, and average vascular area.

　　(3) There are many perspectives in comparative medicine on the mechanism of DCV, but most tend to focus on functional changes rather than structural changes. Due to the influence of perfusion pressure, pH value, physical and chemical factors on large arteries during perfusion fixation, observing the lesions of large arteries may not necessarily reflect the changes in DCV accurately. Reflecting DCV through changes in microvessels is more reliable than reflecting changes in large blood vessels around the cerebral arterial ring. The direct injection of blood through the subarachnoid space above the cerebellar tentorium to the area around the cerebral artery ring simulates the pathological process of SAH more realistically, with simple operation and easy control of bleeding, making it a reliable SAH model. Due to its good repeatability, this model is suitable for the study of DCV.