High dose Allura Red, rather than the ADI dose, induces structural and behavioral changes in the medial prefrontal cortex of rats and taurine can protect it

Abstract

Allura Red is a food color that can lead to neurotoxicity. Taurine is an organic compound that can act as a neuroprotectant. This study aimed to assess the effects of Allura Red with or without taurine consumption on rats’ medial Prefrontal Cortex (mPFC). The subjects were divided into six groups as follows: distilled water, taurine (200 mg/kg/day), and low (7 mg/kg/day = acceptable daily dose), and high (70 mg/kg/day) doses of Allura Red with or without taurine consumption for six weeks. The results of novel objects recognition and eight-arm radial maze tests indicated impairment of memory in the Allura Red groups. Subsequently, their brains were analyzed using stereological methods. Both doses of Allura Red caused an increase in working and reference memory errors during the acquisition and retention phases in comparison to the distilled water group (p < 0.01). Additionally, the high dose of Allura Red led to a reduction in the volume of mPFC (35%) and its subdivisions, number of neurons (59%) and glial cells (46%), length of dendrites, and number of spines (mushroom and thin) per dendritic length in comparison to the distilled water group (p < 0.05). The low dose group only showed a reduction in the number of glial cells. However, simultaneous treatment of rats with taurine plus Allura Red prevented the above-mentioned changes. The acceptable daily dose of Allura Red could bring about impairment in spatial learning and memory as well as in the number of glial cells. On the other hand, the high dose of Allura Red could impair learning, memory, and mPFC structure. Thus, taurine could act as a neuroprotectant.