Background: Diabetes mellitus is a chronic disease that is associated with numerous complications like peripheral neuropathies. It has been shown that hyperglycemia may contribute to its development but the exact pathophysiology underlying this complication has not been fully understood. Since it has been suggested that oral magnesium supplementation can prevent hyperglycemia induced by diabetes, this study was designed to examine the protective effect of oral magnesium administration on thermal hyperalgesia in streptozocin (STZ) induced diabetic rats.

Methods: Male adult wistar rats were divided equally into control, magnesium-treated control, diabetic and magnesium-treated diabetic groups. In magnesium-treated diabetic rats, magnesium sulfate (10 gr/L) was added into drinking water since diabetes was established (10 days after STZ injection) and continued for 8 weeks. Mg-treated control animals received magnesium sulfate in the same dose and time period. The other two groups; control and diabetic animals, only received tap water.

Results: A significant decrease in thermal pain threshold and plasma magnesium levels and also a dramatic increase in plasma glucose levels were seen in diabetic rats eight weeks after diabetes induction. Eight weeks magnesium therapy after the diagnosis of diabetes, could prevent reduction in thermal pain threshold and also restore plasma magnesium and glucose levels in magnesium-treated diabetic animals.

Conclusion: Oral magnesium can prevent hypomagnesaemia, hyperglycemia and thermal hyperalgesia in diabetic rats.