Effectiveness of low-power laser therapy in improvement of the peripheral neuropathy induced by xenobiotics in rats

Abstract

Background: Peripheral neuropathy (PN) is the damage and dysfunction of neurons of the peripheral nervous system. The present study was conducted to estimate the effectiveness of low-power laser therapy (LPLT) in the management of PN in a rats' model.

Methods: PN was induced by giving dichloroacetate (DCA) (250 mg/kg/day) for up to 12 weeks. Four groups of rats were used: control group, PN group, PN group treated with gabapentin and PN group treated with LPLT. The study was conducted for 8 weeks. The management of PN was estimated by behavioral tests which included hot plate and Morris water maze tests. Blood biochemical analysis were carried out.

Results: Using of hot plate test indicated thermal hypoalgesia and using Morris water maze test showed cognitive decline in PN rats. Treatment with LPLT or gabapentin improved both the pain sensations and deteriorated memory that occurred in the PN rats. Biochemical analysis showed that LPLT significantly decreased the elevated beta-endorphin level in PN rats, while gabapentin could not reduce it. Treatment PN rats with LPLT or gabapentin shifted the high levels of TNF-α, IL-1β and IL-10 cytokines back to their normal values. Serum nitric oxide and MDA significantly increased in the PN group together with significant reduction in the rGSH level, these values were significantly improved by LPLT application while this was not the case with gabapentin treatment. Furthermore, treatment with gabapentin or LPLT significantly reduced serum ALAT and ASAT activities which are otherwise increased in the PN group. S100B, PGE2, total cholesterol, triglycerides, LDL-cholesterol, HDL-cholesterol, urea and creatinine showed insignificant changes among all groups.

Conclusions: Our results showed that treatment with LPLT is more efficient than gabapentin in ameliorating the peripheral neuropathy induced by xenobiotics.

Keywords: ADP, adenosine diphosphate; ATP, Adenosine triphosphate; ATP, adenosine triphosphate; DCA, Dichloroacetate; Dichloroacetate; Gabapentin; IL-10, interleukin −10; IL-1β, interleukin - 1β; LPLT, Low power laser therapy; Low-power laser therapy; MCTs, monocarboxylate transporters; MDA, malondialdehyde; NAD+, Nicotinamide adenine dinucleotide; NO, nitric oxide; Neuropathy; PDH, pyruvate dehydrogenase; PGE2, prostaglandin E2; PN, Peripheral neuropathy; S100B, calcium binding protein B; TCA, cycle tricarboxylic acid cycle or the Krebs cycle; TNF-α, tumor necrosis factor- α; rGSH, reduced glutathione.

Fig. 1

Effect of gabapentin and LPLT on levels of serum beta-endorphin and S100B in peripheral neuropathy (PN) modeled rats. Data represent the average ± SD for 10 rats. Means superscript with different letters are significantly different at P ≤ 0.05.

Fig. 2

Effect of gabapentin and LPLT on activities of serum ALAT and ASAT of peripheral neuropathy (PN) modeled rats. Data represent the average ± SD for 10 rats. Means superscript with different letters are significantly different at P ≤ 0.05.

Fig. 3

Effect of gabapentin or LPLT on levels of serum urea and creatinine in peripheral neuropathy (PN) modeled rats. Data represent the average ± SD for 10 rats. Means superscript with different letters are significantly different at P ≤ 0.05.