Soy-containing diet suppresses chronic neuropathic sensory disorders in rats

Partial sciatic nerve ligation (PSL) in rodents produces chronic neuropathi c sensory disorders resembling neuropathic pain in humans. We previously re ported that levels of allodynia and hyperalgesia after PSL injury were mark edly attenuated by consumption of soycontaining diets. Here we aimed to sho w that dietary effect on pain behavior is not specific to a certain laborat ory. For this purpose, experiments were conducted in a different laboratory (Baltimore rather than Jerusalem) and a different rat strain (Wistar rathe r than Sabra), with additional and different testing methods (radiant heat from a lamp rather than a CO, laser). Rats were fed two soy-free diets and a soy-containing one for 28 days. The sensitivity of rats to nonnoxious and noxious stimuli was determined before PSL injury, and levels of neuropathi c sensory disorders were determined after it. We found that consuming the s oy-containing diet prevented development of tactile and heat allodynia, but not mechanical hyperalgesia. This dietary effect was not correlated with c alorie intake and weight gain or dietary concentration of fat and carbohydr ates. We conclude that, regardless of experimental site, diet markedly affe cts chronic neuropathic sensory disorders in rats and should be standardize d in animal models of pain.