Nissl bodies are rough endoplasmic reticulum where proteins are synthesized. They are widely used to reflect the neural structure of the brain and spinal cord and are considered to be related to the nutritional condition of neurons. They may dissolve and even disappear under pathological condition.There are many studies shown that neuronal damage in the spinal cord after spinal cord injury is closely related to decreased amount of Nissl bodies. So, my query when do I perform Nissl staining to get very good results after spinal cord injury in rat animal model?