Development of Hymenolepis diminuta (Rudolphi, 1819) in Mice Made Obese by Aurothioglucose

Abstract

Of 182 Swiss-strain mice injected intramuscularly with aurothioglucose 37 ultimately became obese. Development of obesity was followed for 100 days with records of food consumed, gains in weight, and fecal production. Eighty days after injections ten obese and ten control mice were multiply infected with pretreated cysticercoids of Hymenolepis diminuta. Ten days later hosts were sacrificed and tapeworms recovered. Lengths and weights were recorded and whole mounts prepared. Obese hosts consumed on the average 3 g more food per day, were 2.3 times heavier, and had small intestines one-third longer than control mice, and yielded, unexpectedly, worms significantly shorter and lighter in weight than those from normal mice. Moreover, worms from obese hosts had only 35 nearmature and mature proglottids; whereas, worms from controls had 117. Possible explanations of these inhibitions are discussed. Albino mice can be induced by injections of aurothioglucose to become obese (Brecher and Waxier, 1949; Waxier and Brecher, 1950). Obesity results from overeating following, it is believed (Liebelt and Perry, 1957), chemical destruction of the satiation center of the hypothalamus. These mice show increases in adipose tissue, hepatic centro-lobular infiltration of fat, and histochemically demonstrable gold in the reticulo-endothelial cells of various organs (Waxler and Brecher, 1950). The main purpose of the present investigation was to determine whether increased amounts of food passing through the digestive tract of Swiss-strain mice made obese by gold thioglucose would affect the growth of the tapeworm Hymenolepis diminuta. MATERIALS AND METHODS Aurothioglucose is used medically in the alleviation of arthritic and other symptoms. A commercial product (Solganal, Schering Corporation, Bloomfield, New Jersey), consisting of a 10% suspension (100 mg/ml) of gold thioglucose in sesame oil with 2% aluminum stearate, was used for the injections. Mice, 18 to 25 g, were given total intramuscular injections of 20 to 25 mg of Received for publication 11 January 1963. * This investigation was supported in part by Research Grant PHS E-795 from the Institute of Allergy and Infectious Diseases, National Institutes of Health, Public Health Service. aurothioglucose divided into two equal doses into each thigh. The LD5o for such injections is 23 mg for a 20-g mouse (Waxler and Brecher, 1950). One-third of mice surviving this injection usually become obese (Waxler and Brecher, loc. cit.), and although both sexes are susceptible, only males were used because they tend to exceed females in obesity (Brecher and Waxier, 1949). Control mice were randomly selected from the same weight and age groups. Data on food consumed, feces produced, and weight changes in the mice were collected at frequent intervals. Mice were housed in individual cages beneath which were placed aluminum foil trays lined with paper toweling to absorb urine. Each day the contents of these trays were collected, dried for 24 hr at room temperature, and sifted to separate food particles from the droppings. The food consumed was the amount in the tray plus that still in the cage subtracted from the weighed daily amount given. The separated fecal pellets were sealed in aluminum foil, frozen, and finally weighed after drying at 120 C for 24 hr. All mice were weighed every 5 days. One hundred eighty-two mice were used; of these 107 survived (59%) and 37 (35% of survivors) became obese. Ten obese mice (56.7 g mean weight) and ten normal mice (24.4 g mean weight) were each given seven cysticercoids of H. diminuta which had been pretreated with 0.5% pepsin in 0.85% saline for 12 to 14 hr. Obese mice were challenged 80 days postinjection with aurothioglucose. Both groups of mice were the same age at challenge and were fed, postinfection, ad lib. on laboratory chow (Purina-Ralston Co., St. Lo is, Missouri). Mice were sacrificed 10 days after challenge and all tapeworms recovered. After physical measure-