Effects of Alpha Lipoic Acid Treatment on Laminin Alteration of the Sciatic Nerve in Streptozotocin Induced Diabetic Rats

Neuropathy is one of the most complications of diabetes that may be associated with changes in the structure and function of the basement membranes in nerves. Laminin is one of the most important components of basement membranes in sciatic nerve.

In this study, the protective effects of Alpha lipoic acid (ALA) as an antioxidant agent on blood glucose level, body weight and laminin expression in sciatic nerve of diabetic rats has been evaluated.

 24 adult male rats were randomly divided into 3 groups: control, untreated diabetic and diabetic treated with ALA. Diabetes was induced in the rats by a single dose injection of streptozotocin (55 mg/kg). 12 weeks after treatment, body weight and blood glucose levels were measured and then rats were anesthetized and sciatic nerves were removed and alterations in laminin expression has been evaluated by immunohistochemical study and Real time PCR method. Statistical evaluation was carried out by using one way ANOVA followed by Tukey test.

Untreated diabetic rats showed a significant increase in laminin expression in the perineurium, around the Schwann cells and blood vessels walls of the sciatic nerves (P < 0.05). ALA treatment did not affect on body weight, but significantly decreased blood glucose levels (P < 0.05). ALA treatment significantly decreased laminin expression only in the blood vessels walls of sciatic nerves (P < 0.05). Laminin β1 mRNA level in sciatic nerve of untreated diabetic rats increased 0.6 fold compared to control rats (P < 0.05). Although ALA decreased this up regulation but it was not significant.

 The results indicated that untreated diabetic neuropathy in rat might be associated with increased laminin expression in sciatic nerve and also it may be assumed that ALA treatment protected the blood vessels walls of nerves against laminin over expression in STZ induced diabetic rats.