Investigating the beneficial effect of aliskiren in attenuating neuropathic pain in diabetic Sprague-Dawley rats

Objectives

Worldwide, diabetic neuropathy (DN) is a major complication of diabetes mellitus. The direct renin inhibitor aliskiren is recognized as a treatment for cardiovascular disease in diabetic patients, but little is known about its potential benefits in cases of diabetic neuropathy. Accordingly, we investigated the effects of aliskiren (ALIS) and gliclazide (GLZ) and their combination therapy on peripheral neuropathy in streptozotocin-induced diabetic rats.

Methods

In total, 112 adult Sprague-Dawley rats were used for this study. Diabetes was induced using streptozotocin (STZ), whereas the control group was treated with an equal volume of citrate buffer. The diabetic rats were divided randomly into six groups according to the proposed treatment regime: diabetic control (DC), gliclazide (GLZ), aliskiren (ALIS), ramipril (RAM), (GLZ + ALIS) and (GLZ + RAM). Behavioural responses to thermal (hot-plate) and mechanical (tail-pinch) pain were evaluated. After eight weeks of daily treatments, the animals were fasted and sacrificed. The blood samples were collected, with the serum separated and subjected to various biochemical and enzyme analyses so as to assess the effect of the treatments on diabetic peripheral neuropathy.

Results

After 8 weeks, aliskiren alone and in combination with gliclazide therapy had a significant effect (P < .001) in reducing blood glucose levels and showed increased hot-plate and tail-flick latencies compared with the diabetic control group. The threshold of mechanical hyperalgesia was also significantly elevated (P < .001).

Conclusions/Interpretations

These data suggest that either aliskerin alone or in combination with gliclazide can protect against the development and progression of diabetic neuropathy.