Changes of Tissue Histopathology and Uric Acid Excretion in Silkworm Larvae Intoxicated with Deoxypodophyllotoxin and Racemomycin-D, and during Starvation

Abstract

Histopathological examination of tissues and analysis of uric acid in hemolymph and feces of the 5th instar larvae of the silkworm, Bombyx mori LINNE, either treated with racemomycin-D or deoxypodophyllotoxin both of which showed delayed insecticidal activities, or being starved, gave the following results. 1) In the larvae treated with racemomycin-D the epidermal cells and fat body cells were seriously damaged along with the Malpighian tubules, 2) in the larvae treated with deoxypodophyllotoxin, the fat body cells as well as the epidermal cells were seriously damaged, but the Malpighian tubules remained intact, 3) on starvation, only the fat body cells were damaged. 4)Both in the starved and the deoxypodophyllotoxin-treated larvae, a considerable increase of uric acid was noted in hemolymph and feces.It was concluded that the increase of uric acid in hemolymph and feces was caused by the histolysis of fat body cells due to inadequate feed intake, resulting either directly therough starvation or indirectly through the effects of the chemicals.