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Pesticides
Roundup: Popular herbicide more deadly to liver cells than
its active chemical alone
Embryonic and placental cells are also affected by Roundup (3). Furthermore,
"Chemical mixtures in formulations appear to be underestimated regarding their
toxic or hormonal impact." (3)
1.
Popular herbicide more deadly to liver cells than its active chemical alone.
18 August 2009
- Scientists report that a number of Roundup formulations tested at very
dilute concentrations can alter hormone actions and cause human liver cells
to die within 24 hours of treatment. The key factor affecting how dangerous
the different formulations were lay in their "inert ingredients" ...
chemicals usually protected by trade secrets clauses.
2. Glyphosate-based herbicides are toxic and
endocrine disruptors in human cell lines
Gasnier C et al.
Toxicology. 2009 Aug 21;262(3):184-91.
Glyphosate-based herbicides are the most widely used across the world; they are
commercialized in different formulations. Their residues are frequent pollutants
in the environment. In addition, these herbicides are spread on most eaten
transgenic plants, modified to tolerate high levels of these compounds in their
cells. Up to 400 ppm of their residues are accepted in some feed. We exposed
human liver HepG2 cells, a well-known model to study xenobiotic toxicity, to
four different formulations and to glyphosate, which is usually tested alone in
chronic in vivo regulatory studies. We measured cytotoxicity with three assays (Alamar
Blue, MTT, ToxiLight), plus genotoxicity (comet assay), anti-estrogenic (on
ERalpha, ERbeta) and anti-androgenic effects (on AR) using gene reporter tests.
We also checked androgen to estrogen conversion by aromatase activity and mRNA.
All parameters were disrupted at sub-agricultural doses with all formulations
within 24h. These effects were more dependent on the formulation than on the
glyphosate concentration. First, we observed a human cell endocrine disruption
from 0.5 ppm on the androgen receptor in MDA-MB453-kb2 cells for the most active
formulation (R400), then from 2 ppm the transcriptional activities on both
estrogen receptors were also inhibited on HepG2. Aromatase transcription and
activity were disrupted from 10 ppm. Cytotoxic effects started at 10 ppm with
Alamar Blue assay (the most sensitive), and DNA damages at 5 ppm. A real cell
impact of glyphosate-based herbicides residues in food, feed or in the
environment has thus to be considered, and their classifications as
carcinogens/mutagens/reprotoxics is discussed.
3: Time- and dose-dependent effects of roundup on
human embryonic and placental cells.
Benachour N et al.
Arch Environ Contam Toxicol. 2007 Jul;53(1):126-33.
Roundup is the major herbicide used worldwide, in particular on genetically
modified plants that have been designed to tolerate it. We have tested the
toxicity and endocrine disruption potential of Roundup (Bioforce on human
embryonic 293 and placental-derived JEG3 cells, but also on normal human
placenta and equine testis. The cell lines have proven to be suitable to
estimate hormonal activity and toxicity of pollutants. The median lethal dose
(LD(50)) of Roundup with embryonic cells is 0.3% within 1 h in serum-free
medium, and it decreases to reach 0.06% (containing among other compounds 1.27
mM glyphosate) after 72 h in the presence of serum. In these conditions, the
embryonic cells appear to be 2-4 times more sensitive than the placental ones.
In all instances, Roundup (generally used in agriculture at 1-2%, i.e., with
21-42 mM glyphosate) is more efficient than its active ingredient, glyphosate,
suggesting a synergistic effect provoked by the adjuvants present in Roundup. We
demonstrated that serum-free cultures, even on a short-term basis (1 h), reveal
the xenobiotic impacts that are visible 1-2 days later in serum. We also
document at lower non-overtly toxic doses, from 0.01% (with 210 microM
glyphosate) in 24 h, that Roundup is an aromatase disruptor. The direct
inhibition is temperature-dependent and is confirmed in different tissues and
species (cell lines from placenta or embryonic kidney, equine testicular, or
human fresh placental extracts). Furthermore, glyphosate acts directly as a
partial inactivator on microsomal aromatase, independently of its acidity, and
in a dose-dependent manner. The cytotoxic, and potentially endocrine-disrupting
effects of Roundup are thus amplified with time. Taken together, these data
suggest that Roundup exposure may affect human reproduction and fetal
development in case of contamination. Chemical mixtures in formulations appear
to be underestimated regarding their toxic or hormonal impact.