Expression of synaptic cell adhesion molecule 1 (SynCAM 1) in different brain regions in a rat subarachnoid hemorrhage model.

Synapses, the junctions between nerve cells through which they communicate, are formed by the coordinated assembly and tight attachment of pre- and postsynaptic specializations. Synaptic cell adhesion molecule 1 (SynCAM 1) has been proved to be an important factor for synapse function and behavior cognition. The current research aimed to investigate the expression of the SynCAM 1 in the brain after experimental subarachnoid hemorrhage (SAH) in rats. A total of 42 rats were randomly divided into seven groups: control group, sham group, day 1, day 3, day 5, day 7, and day 14 groups. Day 1, day 3, day 5, day 7, and day 14 groups were all SAH groups in which the rats were killed on days 1, 3, 5, 7, and 14, respectively. The rat SAH model was induced by injection of 0.3 ml fresh arterial, non-heparinized blood into the prechiasmatic cistern in 20 s. Immunostaining and immunoblotting experiments were performed to detect the expression of SynCAM 1 protein. The clinical behavior scale was measured on day 14 after SAH. The expression of SynCAM 1 protein was decreased remarkably in SAH groups compared with the sham group. The down-regulated expression of SynCAM 1 was detected after SAH and the low ebb was on days 1-3. The immunohistochemical staining demonstrated expression of SynCAM 1 was present mainly in the neurons in all of the three different regions such as cortex, hippocampus, and cerebellum. The clinical behavior scale was significantly decreased compared with sham rats. Our results indicate that SynCAM 1 expression is down-regulated in the brain after experimental SAH. These finding suggests that decreased SynCAM 1 expression may facilitate the development of cognitive dysfunction after SAH.