A 90-day toxicity study of GmTMT transgenic maize in Sprague-Dawley rats

GmTMT transgenic maize is a genetically modified maize plant that overexpresses the gamma-tocopherol methyltransferase (gamma-TMT) from Glycine max (Gm). The gamma-TMT gene was introduced into maize line Zhen58 to encode the GmTMT2a protein which can convert gamma-tocopherol into alpha-tocopherol. Over expression of GmTMT2a significantly increased the alpha-tocopherol content in transgenic maize. The present study was designed to investigate any potential effects of GmTMT maize grain in a 90-day subchronic rodent feeding study. Maize grains from GmTMT or Zhen58 were incorporated into rodent diets at low (12.5%), medium (25%) or high (50%) concentrations and administered to Sprague-Dawley rats (n = 10/sex/group) for 90 days. The negative control group of rats (n = 10/sex/group) were fed with common maize diets. Results from body weights, feed consumption, clinical chemistry, hematology, absolute and relative organ weights indicated no treatment-related side effects of GmTMT maize grain on rats in comparison with rats consuming diets containing Zhen58 maize grain. In addition, no treatment related changes were found in necropsy and histopathology examinations. Altogether, our data indicates that GmTMT transgenic maize is as safe and nutritious as its conventional non-transgenic maize. (C) 2017 Elsevier Inc. All rights reserved.