Expression profiling of key pathways in rat liver after a one-year feeding trial with transgenic maize MON810

Abstract

In a recent one-year feeding study, we observed no adverse effects on tissue level in organs of rats fed with the genetically-modified maize MON810. Here, we assessed RNA expression levels of 86 key genes of the apoptosis-, NF-кB-, DNA-damage response (DDR)-, and unfolded-protein response (UPR) pathways by RT-qPCR in the rat liver. Male and female rats were fed either with 33% MON810 (GMO), isogenic- (ISO), or conventional maize (CONV) and RNAs were quantified from eight rats from each of the six feeding groups. Only Birc2 transcript showed a significant (p ≤ 0.05) consistent difference of ≥1.5-fold between the GMO and ISO groups in both sexes. Unsupervised cluster analysis showed a strong separation of male and female rats, but no clustering of the feeding groups. Individual analysis of the pathways did not show any clustering of the male or female feeding groups either, though transcript levels of UPR pathway-associated genes caused some clustering of the male GMO and CONV feeding group samples. These differences were not seen between the GMO and ISO control or within the female cohort. Our data therefore does not support an adverse effect on rat liver RNA expression through the long-term feeding of MON810 compared to isogenic control maize.

Subacute toxicity studies of meals prepared from genetically modified potato overexpressing the StDREB1 or the VvWRKY2 transcription factor in rats

“…These results are in accordance with those of Rhee et al ., 21 who demonstrated that the consumption of GMPs did not have negative effects on the fertility of rats. The absence of adverse effects in our study are consistent with those described in other studies in which processed GM crops with enhanced agronomic traits have shown the absence of clinical effects or histopathological abnormalities in the organs or tissues of animals 22‐37 . Other safety assessment studies of GMPs showed the absence of negative effects on rats 19,38,39 .…”

“…The absence of adverse effects in our study are consistent with those described in other studies in which processed GM crops with enhanced agronomic traits have shown the absence of clinical effects or histopathological abnormalities in the organs or tissues of animals. [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] Other safety assessment studies of GMPs showed the absence of negative effects on rats. 19,38,39 In contrast, in some cases, side effects have been detected in GMP-fed rats.…”

Development and Adoption of Genetically Engineered Plants for Virus Resistance: Advances, Opportunities and Challenges

“…While it must be stressed that some of the concerns raised about GM crops are founded and should be addressed prior to release, a lot of the opposition is either out of ignorance or it is outright manipulative. For example, as discussed in this review, there are claims that GM crops adversely affect humans and animals [81], yet there is no empirical data supporting this assertion. Furthermore, suggestions that transgenes will contaminate the environment appear to assume that transgenes, including those derived from virus genomes, are by their nature harmful to the environment.…”

“…The possible adverse effects of transgenes to humans and animals, as well as to the plants have been expressed. However, an investigation of GM maize in rats either showed no negative effect [81] or the toxicity observed was due to herbicides that were used to control weed in the experiments, and not to the transgene [81,82]. With regards to GE for virus resistance, most viral resistance transgenes are designed from viral genes or segments, which are also present in foods from infected non-GM crops.…”