MATERIAL and METHODS: Microtubules in neurons mediate both the consciousness and memory and regulate firing. Microtubuleassociated proteins promote microtubule organisation and dynamics. We investigated MAP2, tau and amyloid beta levels in the hippocampus and the frontal cortex after experimental subarachnoid haemorrhage in rats. Subjects were divided into subgroups and were housed either in an enriched, standard or isolated environment. Tissue levels were measured on day 7 for short-term outcomes and on day 14 for long-term outcomes after subaracnoid haemorrhage.

RESULTS: After subaracnoid haemorrhage, decreased microtubule-associated proteins 2 levels, a trend in pathologic tau accumulation and increased amyloid beta levels in different brain regions of rats kept in an isolated environment. Frontal lobe microtubule-associated proteins 2 levels were increased in rats kept in an enriched environment for 7 days. Pathological hippocampal tau and frontal lobe amyloid beta levels were increased in rats kept in an isolated environment for 7 days. Increased microtubuleassociated proteins 2 levels in the hippocampus, decreased frontal and hippocampal amyloid beta were seen in rats kept in an enriched environment for 14 days.

CONCLUSION: Although it would be too early to offer recommendations, results of the present study support that an enriched environment may be more valuable in the follow-up of subaracnoid haemorrhage. Further experimental studies would provide more reliable results to facilitate discussions about how to optimise the patient’s environmental conditions. Keywords : Subarachnoid haemorrhage, Environmental conditions, Rat, MAP2, Tau, Amyloid beta