HISTOMORPHOMETRY OF MYENTERIC PLEXUS NEURONS OF THE HORSE DESCENDING COLON AFTER EXPOSURE TO BENZALKONIUM CHLORIDE.

Abstract

We evaluated the effects of benzalkonium chloride (BC) on the morphometry of the myenteric plexus neurons of the descending colon in eight horses. Two animals were euthanased at day 1, two at day 3, and four at day 15. Samples of the treated intestinal segment were obtained, as well as samples of the same intestinal segment from ten untreated horses slaughtered in a meat packing plant and used for comparison. Histomorphometry of the myenteric plexus neurons was performed with an image analyzer. There was a reduction in the number of myenteric plexus neurons after treatment with BC and the remaining neurons showed smaller mean neuronal body, cytoplasm and nucleus areas than control animals, especially in animals slaughtered at day 3, whereas animals slaughtered at day 15 presented values close to those of control animals. We concluded that the myenteric plexus neurons of the horse descending colon presented smaller neuronal bodies at fifteen days after exposure to BC in comparison with controls, thus showing no signs of neuroplasticity. KEY -WORDS: Myenteric plexus. Benzalkonium chloride. Morphometry. Neuroplasticity. Horses.