Lésions provoquées chez le criquet Gomphocerus Sibiricus par l'absorption de benzo-a-pyrène et de 3-méthylcholanthrène

Abstract

Using UV light in order to study accumulation of BaP or 3MC by Gomphocerus sibiricus, a locust strictly located between 2 000 and 2 800 m, we have previously shown that these HAP can be rapidly absorbed by midgut, then, accumulated in many organs and essentially eliminated by Malpighian tubules (J.B., 1999), presumably after partial degradation. Now we describe the effects of these carcinogenic polycyclic hydrocarbons at histological and cytological levels. Wholly invaded, midgut epithelium is profoundly intoxicated, numerous cells showing structural abnormalities or beeing destroyed: excessive merocrine secretion becoming finally holocrine. Connective and muscular tissues do not constitute effective barriers against toxic effects of the HAP. Fat body and muscles, though strongly impregnated with each of them, show only discrete cellular damage. Locally, the reproductive system is more clearly affected. Otherwise, nervous cord ganglia contain some dead cells, and we describe an effective swelling of the intercellular spaces. This point seems to imply disturbancies of the glial sheats which isolate neurons from their neighbours. Finally, digestive caeca, strongly affected by HAP, are partly destroyed, especially after treatment by BaP. We suggest caeca could be a secondary route of degradation and excretion of HAP. Tubes of Malpighi seem to be the principal route of their elimination; their epithelium is frequently severely injured and may sometimes disappear. As with mammals, we have to underline here similar differential cell susceptibilities within each organ of a locust. However what may be, we have perceived effective disturbancies which are strong enough to involve a knock-down and finally death of a part of the treated locusts. This work gives us new opportunities for ulterior research, for example, with locusts sampled in a variety of biotopes, strongly polluted or “not”. Our UV test may be used as a first approach.