To study the effect of long-term exposure to a modulated magnetic field, insulin, and their combination on blood-brain barrier permeability (30 days after the beginning of the experiments) in a diabetic rat model.
The effects of diabetes mellitus on the blood-brain barrier are contradictory.
53 rats were randomly assigned to one of six groups: 1) sham exposure; 2) magnetic field exposure; 3) diabetes mellitus induced with streptozotocin; 4) diabetes mellitus plus magnetic field exposure; 5) diabetes mellitus plus insulin therapy; and 6) diabetes mellitus plus insulin therapy plus magnetic field exposure.
rats were divided into six groups: i) sham exposure ii) EMF exposure iii) diabetes mellitus induced iv) diabetes mellitus induced + EMF exposure v) diabetes mellitus induced + insulin therapy vi) diabetes mellitus induced + insulin therapy + EMF exposure
The extravasation of evans blue of the groups 2-6 was higher than that of sham exposure group (group 1) and the extravasation of the right hemisphere of group 6 (diabetes mellitus plus insulin therapy plus magnetic field exposure) was the highest. The data showed that streptozotocin-induced diabetes mellitus appears to increase the vulnerability of the blood-brain barrier during magnetic field exposure.
A significant increase of mean arterial blood pressure was observed in all streptozotocin-induced diabetic rats, but the magnetic field caused no additional effect. The post-procedure body mass of the sham exposure and the exposure group (group 1 and 2) were significantly higher than those of the "diabetes mellitus group" and "diabetes mellitus plus magnetic field exposure group" (group 3 and 4). In the diabetic groups 3-6 the baseline glucose (before treatment) was significantly lower than the post-procedure glucose level.
Diabetes mellitus and magnetic field exposure increased blood-brain barrier permeability; in combination, they caused a higher increase in blood-brain barrier permeability, and insulin decreased their effect (it prevents the disturbing effect of magnetic field exposure). Improved glucose metabolism may prevent body mass loss and the hypoglycemic effect of magnetic field. Further studies are needed to evaluate the clinical relevance of the relationship of diabetes mellitus with or without insulin therapy and magnetic field exposure.