[Expression of IL-1 mRNA and its correlation with astrocytes and NOS-positive neurons in rat spinal cord following sciatic nerve injury].

OBJECTIVE

To study expression of Interleukin 1 (IL-1) and its correlation with astrocytes and nitric-oxide synthase (NOS)-positive neurons in rat spinal cord following sciatic nerve transection.

METHODS

Using RT-PCR and immunohistochemistry methods.

RESULTS

The experiments showed that IL-1 expression appeared with a low frequency at 3 days after the axontomy, while it could be markedly detectable on post-lesioned day 7 and 14. In normal controls and the spinal fragments without being involved in the injury, no signal of IL-1 mRNA expression was detected with the same condition. At 7 days after nerve injury, the lesioned side of spinal cord began to show strong glial fibrillary acidic protein (GFAP) immunoreactive astrocytes and induction of NOS in the motoneurons that are normally NOS-negative. Up to 21 days after operation, GFAP staining showed star-shaped astrocytes closely resembling the typical appearance of fibrous astrocytes and GFAP-immunoreactive profiles were often seen surrounding NOS-positive neurons. Analysis of the time course of IL-1 mRNA expression, appearance of NOS-positive neurons and changes of reactive astrocytes suggested a close relationship between them.

CONCLUSIONS

IL-1, NO might function as important mediators between injured motoneurons and astrocytes.