Effects of Insulin-induced Hypoglycemia on Cerebrovascular Permeability in Diabetic Rats

報告番号(甲第19号)We studied the effect of insulin-induced hypoglycemia in both normal and streptozotocin-diabetic rats with two different durations of diabetes : 3 months and 6 months. The study was carried out in order to investigate : (a) whether diabetes alters cerebrovascular permeability, (b) whether the alteration of cerebrovascular permeability is changed by insulin-induced hypoglycemia. and (c) the relationship between the duration of the diabetic state and blood-brain barrier permeability. Evans blue fluorescence was used as an albumin tracer. In the basal condition, diabetic rats showed a significant increase in cerebrovascular permeability compared with normal rats. Insulin-induced hypoglycemia significantly enhanced cerebrovascular permeability in both normal rats and diabetic rats. the 6-month diabetic rats demonstrated a significant increase in cerebrovascular permeability ompared with the 3-month diabetic rats. In summry, insulin-induced hypoglycemia was thus demonstrated to be associated with a significant increase of cerebrovascular permeability in diabetic rats in relation to the duration of their diabetic state. Although the clinical sigificance of the findings still remains unknown, the results suggest the possibility that a similar phenomenon might also occur in the brain of long-term diabetic patients with severe and prolonged hypoglycemia.博士(医学)琉球大