Minocycline reduces proinflammatory and oxidative stress markers in the spinal cord and morphology changes in sciatic nerve of Type 2 diabetic neuropathy rat model.

Aim: This study investigated the effects of minocycline on proinflammatory cytokines, oxidative stress marker levels in the spinal cord and sciatic nerve morphology in Type 2 diabetic (T2DM) neuropathy rats.

Methods: Male Sprague Dawley rats were randomly assigned to six groups ( = 14 per groups): Control (C), T2DM control (STZ), T2DM treated with minocycline 40 mg/kg (STZ + M40) and 80 mg/kg (STZ + M80), T2DM treated with gabapentin (STZ + G10) and non-painful T2DM neuropathy (NPDN). T2DM was induced in obese rats using a combination of high fat diet (HFD) and low-dose streptozotocin (STZ) (40 mg/kg) injection. Then, the neuropathic pain behaviour, body weight and blood biochemical analysis were performed. Rats were sacrificed and the spinal cord and sciatic nerve were collected for ELISA and histology examination.

Results: T2DM rat groups were significantly increased body weight after 6 weeks but significantly reduced from 8 until 9 weeks compared to control group ( < 0.05). The fasting blood glucose (FBG) level in all T2DM groups were significantly higher on day 3, day 14, and day 22 compared to control group ( < 0.05) consistent with HbA1c levels. T2DM groups also significantly increased MDA, TNF-α, IL-1β and C-Reactive Protein (CRP) but decreased SOD and Catalase levels in the spinal cord compared to control group ( < 0.05). T2DM groups also showed significant abnormal morphology changes in the sciatic nerve compared to control group ( < 0.05). Minocycline dependent on doses and gabapentin in T2DM rat significantly alleviated all these effects.

Conclusion: These findings suggest the neuroprotective effects of minocycline on T2DM neuropathy.