Evaluating the Effects of Probiotic Supplementation on Neuropathic Pain and Oxidative Stress Factors in an Animal Model of Chronic Constriction Injury of the Sciatic Nerve

Neuropathic pain is a common and painful somatosensory nervous system disease, and its treatment remains a medical challenge. Evidence demonstrates that gut microbiota alters in neuropathic pain and, therefore, improvement of the gut flora may affect the disease. The present study aimed to evaluate the antinociceptive effect of probiotics in neuropathic pain and oxidative biomarkers’ responsiveness to the probiotic treatment.

Using chronic constriction injury (CCI) of the rats' sciatic nerve, neuropathic pain was induced. Investigating the analgesic effect of the probiotics mixture, 40 male rats were randomly assigned to 4 groups (n=10 for each): Sham-operated (SM), and CCI model rats orally received 1 mL saline (CS), or 100 mg/kg gabapentin (CG) or 1 mL probiotics mixture (CP) Lactobacillus plantarum, Lactobacillus delbrueckii, Lactobacillus acidophilus, Lactobacillus rhamnosus, and Bifidobacterium bifidum (109 CFU of each) daily. Using behavioral tests, the pain was assessed on days 1, 4, 7, 14, and 21 of the study. Finally, the biochemical evaluation of sciatic nerve tissue was done.

Probiotics decreased cold and mechanic allodynia and thermal hyperalgesia. Reducing lipid peroxidation levels and increasing total antioxidant capacity, superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity were also significant in the probiotics group.

These findings suggest that probiotics have analgesic effects on the CCI model of neuropathic pain via increasing the antioxidant capacity of the rats’ sciatic nerve.