Figure 1.

GBH, rather than pure glyphosate, may cause PNS demyelination via undisclosed additives propagating inflammatory glial cell activation.

In an ex vivo model of PNS myelination, freshly explanted murine embryonic DRGs were kept under neurite-stimulating conditions before myelination was induced. In order to test whether pure glyphosate or GBH may interfere with myelination or cause demyelination, either compound was added to cultures directly at the start of myelination-induction or to cultures with pre-existing myelin, respectively. Quantification of myelination was performed by Sudan Black staining to determine the number of internodes per neurons in individual cultures wells. Whereas pure glyphosate did not affect internodal density, GBH treatment was associated with a concentration-dependent reduction in the number of internodes. The demyelinating effect of the GBH was associated with a marked induction of TNF-α in Schwann cells. These findings suggest that GBH might impede the formation and maintenance of myelin sheaths via a mechanism involving inflammatory glial cell activation. GBH: Glyphosate-based herbicide; PNS: peripheral nervous system; DRGs: dorsal root ganglions; TNF-α: tumor necrosis factor-alpha.