Thiamine, pyridoxine, cyanocobalamin and their combination inhibit thermal, but not mechanical hyperalgesia in rats with primary sensory neuron injury

Abstract

Neuropathic pain after nerve injury is severe and intractable, and current drugs and nondrug therapies offer substantial pain relief to no more than half of affected patients. The present study investigated the analgesic roles of the B vitamins thiamine (B1), pyridoxine (B6) and cyanocobalamin (B12) in rats with neuropathic pain caused by spinal ganglia compression (CCD) or loose ligation of the sciatic nerve (CCI). Thermal hyperalgesia was determined by a significantly shortened latency of foot withdrawal to radiant heat, and mechanical hyperalgesia was determined by a significantly decreased threshold of foot withdrawal to von Frey filaments stimulation of the plantar surface of hindpaw. Results showed that (1) intraperitoneal injection of B1 (5, 10, 33 and 100 mg/kg), B6 (33 and 100 mg/kg) or B12 (0.5 and 2 mg/kg) significantly reduced thermal hyperalgesia; (2) the combination of B1, B6 and B12 synergistically inhibited thermal hyperalgesia; (3) repetitive administration of vitamin B complex (containing B1/B6/B12 33/33/0.5 mg/kg, for 1 and 2 wk) produced long-term inhibition of thermal hyperalgesia; and (4) B vitamins did not affect mechanical hyperalgesia or normal pain sensation, and exhibited similar effects on CCD and CCI induced-hyperalgesia. The present studies demonstrate effects of B vitamins on pain and hyperalgesia following primary sensory neurons injury, and suggest the possible clinical utility of B vitamins in the treatment of neuropathic painful conditions following injury, inflammation, degeneration or other disorders in the nervous systems in human beings.

Comparative Clinical Trail Of Safety And Tolerability Of Gabapentin Plus Vitamin B1/B12 Versus Pregabalin In The Treatment Of Painful Peripheral Diabetic Neuropathy

“…Our study demonstrates that GBP enhances sleep hours and the perception of improvement of the same, as with PGB, although with lower dose of the former. A study of Lo HS et al showed that GBP increases slow-wave sleep in patients with primary insomnia, improving sleep quality by improving its efficiency and decreasing spontaneous awakenings [22]. It is also worth mentioning that this improved sleep is not related to the presence of daytime sleepiness, as evidenced by the results of our study.…”

“…Also increases afferent inhibitory control of nociceptive neurons of spinal cord, and reduces the thalamic neurons response to nociceptive stimulation [22]. Another effect that explains its antihyperalgesic action is through increasing the synthesis of serotonin and GABA and decreasing glutamate levels in several brain areas [23].…”

Antinociceptive and anti-inflammatory effects of thiamine in Long Evans rats

“…It is noteworthy that, rats treated with high doses of B vitamins have not shown any toxic effects 20 . Moreover, repetitive (chronic) administrations of the B vitamins produced long term inhibition of both severity and duration of pain 20 .…”

“…Moreover, repetitive (chronic) administrations of the B vitamins produced long term inhibition of both severity and duration of pain 20 . Recently, the analgesic and anti-inflammatory effects of thiamine have been demonstrated in different types of animals and the acute and chronic antinociceptive effect of thiamine was evaluated by hot plate test in mice model 21,22 .…”

“…Therefore, this study was designed to evaluate the antinociceptive as well as anti-inflammatory effects of chronic (single daily dose for 7 consecutive days) supplementations of thiamine in increasing doses (100, 200 and 250 mg/kg of body weight) by formalin test and formalin induced paw edema test, in rats. 16,20,22,30,[37][38] : The rats were acclimatized in the experimental laboratory environment, in the observation cage of the plexiglass formalin box (30×30×30 cm3) for 1 hour daily (within 8:00 to 14:00 hours) for 7 consecutive days prior to the formalin test. Then on the day of experiment (Day 7), 1 hour after last dose of (i.p.)…”