Lower faecal egg excretion in chemically-induced diabetic mice infected with Schistosoma mansoni due to impaired egg maturation

Abstract

(Turchetti-Maia et al. 1983), and insulin-dependent diabetes mellitus (Mahmoud et al. 1975) have been described to affect schistosomiasis in laboratory animals. Insulin-dependent diabetes mellitus (IDDM) is a metabolic disease, which is caused by the absence or the impaired functionallity of insulin and is mainly characterized by high blood glucose concentrations. IDDM can be induced in laboratory animals by injection of chemicals, like streptozotocin (STZ) (Rerup & Tarding 1969), which destroy the β-cells in the pancreas.Diabetes mellitus is associated with some defects in the cell-mediated immunity (Mandel & Mahmoud 1978) and individuals who suffer from this disease seem to be more susceptible to bacterial and fungal infections (Hart et al. 1969, Robertson & Polk 1974. In several experiments performed by Mahmoud et al. (1975Mahmoud et al. ( , 1976 and by Mahmoud (1979) netic diabetic mice were infected with Schistosoma mansoni. The results from these experiments showed that there was no difference between control and diabetic littermates in egg output, length and number of worms or in cercariae penetration through the skin. However, the size of the granuloma around the eggs, in both the liver and the lungs, was described to be smaller in diabetic mice. No difference was observed in granuloma formation around foreign bodies (divinyl benzene copolymer beads). These works show that IDDM affects the cell-mediated immune response around S. mansoni eggs in mice. On the other hand eosinophils favour the passage of schistosomal eggs to the intestinal lumen (Lenzi et al. 1987) and mice deprived of their T-cells have fewer eggs in their faeces (Doenhoff et al. 1978). Given that faecal egg excretion depends on the host immune response the present work was initiated to analise whether streptozotocin-induced diabetes mellitus could affect the faecal egg excretion.Swiss Webster mice (5 days old) were infected transcutaneously by exposing them to 50 cercariae (BH strain) of S. mansoni. From 40 days after the infection on, faeces was collected twice a week from each mouse individually. The faeces were processed according to the Kato-Katz method (Katz et al. 1972) and two slides per animal were counted. Forty-seven days after infection, IDDM was induced in 20 mice with an average weight of 33.9 ± 1.3 g by injecting STZ (180 mg per kg bodyweight, ip.) dissolved in citrate buffer (pH 4.5). Control

Decreased basal non-insulin-stimulated glucose uptake by diaphragm in streptozotocin-induced diabetic mice infected with Schistosoma mansoni

“…The egg count in the intestine and liver after dissolving the tissue with 4% KOH showed no statistical significant difference between the two groups. These data are in accordance to Hulstijn et al (2001). However, unlike theirs, the production of viable eggs by the female worm was not affected as evidenced from the oogram of the two groups.…”

Revisiting glucose uptake and metabolism in schistosomes: new molecular insights for improved schistosomiasis therapies

“…The depression in the development of mature eggs following SjIR vaccination supports earlier observations that a low level of insulin in host blood might hamper egg passage through the intestinal tissue (Hulstijn et al, 2001). …”

Parasitological characteristics of Schistosoma mansoni infection in swiss mice with underlying malnutrition

“…In this present experiment, host environmental changes caused by malnutrition have no effect on the worm's ability to produce viable eggs, or on the development of the egg in the intestine tissue, in opposition to schistosome infection in mice with underlying experimental diabetes mellitus (Hulstijn et al 2001).…”