Effects of diet on the lipid composition of Echinostoma caproni (Trematoda) in ICR mice

Effects of Echinostoma caproni infection on the neutral and polar lipids of intestinal and non-intestinal organs in the BALB/c mouse as determined by high-performance thin-layer chromatography

The goal of this study was to characterize and quantify the various neutral and polar lipid classes in the BALB/c mouse that are associated with Echinostoma caproni infection. Ten infected mice and 10 uninfected control mice were used for this study (five infected and five uninfected were used for each of the neutral lipid and polar lipid studies). After 3 weeks postinfection, the mice were necropsied and various organs were removed and prepared for lipid class analysis. The organs used were liver, kidney, spleen, colon, cecum, anterior portion of the small intestine (SI), middle portion of the SI, and posterior portion of the SI. Lipids were determined by high-performance thin-layer chromatography (HPTLC) with Analtech 10 x 20 cm HPTLC-HLF silica gel plates. For neutral lipids, petroleum ether-diethyl ether-glacial acetic acid (80:20:1) mobile phase and 5% ethanolic phosphomolybdic acid detection reagent were used to determine the neutral lipids in each organ. Chloroform-methanol-deionized water (65:25:4) mobile phase and 10% cupric sulfate in 8% phosphoric acid detection reagent were used to determine the polar lipids in each organ. The analyzed polar lipids in all organs were phosphatidylcholine (PC), phosphatidylethanolamine (PE), and sphingomyelin (SM). Using HPTLC-densitometry for quantification, PC was found in the greatest amount and SM the smallest of all organs analyzed. The PE in the anterior portion of the SI was determined to be significantly greater (using the Student's t test with P < 0.05), with about twice the amount of PE in mice infected with E. caproni relative to the uninfected mice. No significant differences in any of the neutral lipid classes were found between infected and uninfected samples.

Light and confocal microscopic observations of adult Schistosoma mansoni from mice fed on a high-fat diet

The morphological aspects of Schistosoma mansoni adult worms recovered from albino mice fed on a cholesterol-rich diet compared to mice fed on a standard chow were investigated. After feeding on their respective diets for over a period of 5 months, mice were subcutaneously infected with c. 50 S. mansoni cercariae/mouse. Blood samples were obtained 1 day prior to experimental infections and 63 days later, when mice were euthanized by jugular section (hypovolaemic shock). Total cholesterol (TC) levels were determined. Recovered worms were stained with hydrochloric carmine, and preserved as whole-mounts for examination by bright-field and laser confocal microscopy. The infected mice fed on high-fat chow showed higher levels of serum lipoproteins than the infected mice fed on standard chow, except for very-low-density lipoprotein cholesterol (VLDL-c) and triglycerides (TG). In this experiment, worms from mice fed on a high-fat chow showed a greater percentage of morphological differentiation regarding supernumerary testes, seminal vesicle, and seminal receptacle. In mice of this group, the rate of oocyte laying in the ovary was much higher than in control females. The present results suggest that cholesterol could be actively involved in the modulation of cell signalling and reproduction, because the lobes contained fully developed oocytes in variable amounts, different from control males. The data presented here are the first to report the role of a cholesterol-rich diet affecting the development of S. mansoni worms.

Effects of Echinostoma caproni infections on metallic ions in the intestinal mucosa of ICR mice

Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to study metallic ions in the intestinal mucosa of ICR mice infected with Echinostoma caproni and the mucosa of uninfected control mice. Infected mucosa (n = 9 with about 100 mg wet weight per sample) were examined at 2 weeks p.i. in mice that were infected with about 25 worms per host. Uninfected mucosa (n = 9 with about 100 mg wet weight per sample) were examined in the same time frame as the infected mucosa. Five metals were measured in the mucosa by ICP-AES analysis, as follows: calcium, potassium, magnesium, sodium and zinc. There were no significant differences (Student's t-test, P > 0.05) in the concentrations of calcium, potassium or zinc in infected versus uninfected mucosa. The concentration of sodium was significantly greater (P < 0.05) in the mucosa of infected versus uninfected mucosa, but the situation was reversed in regard to magnesium.

Effects of tonicity on the release of neutral lipids in Echinostoma caproni adults and observations on lipids in excysted metacercariae

High performance thin layer chromatography was used to analyze neutral lipids in worm incubates isotonic, hypotonic, and hypertonic to the intestinal habitat of adult Echinostoma caproni. Qualitative analysis revealed the presence of free sterols, free fatty acids, triacylglycerols, and a steryl ester/hydrocarbon fraction in all incubate samples. The most abundant neutral lipid fraction released into the incubation medium was the triacylglycerol fraction. This fraction was quantified after worms were maintained for 2 h at 37.5 degrees C in hypertonic (Locke's 2x solution), isotonic (Locke's 0.5x solution) and hypotonic (deionized water) media. Percentages of triacylglycerols on a wet-weight basis found in Locke's 2x, 0.5x, and deionized water were 0.369, 3.23, and 0.242, respectively, suggesting that the optimal medium to obtain maximal excretory-secretory products is the Locke's 0.5x solution. Histochemical staining of whole excysted metacercariae with oil red O did not detect neutral lipids. Analysis of 500 excysted metacercariae incubated for 2 h at 37.5 degrees C revealed that free sterols, free fatty acids, and triacylglycerols were released in amounts of 16.2, 1.59, and 5.34 ng/organism, respectively. Our results were compared with previous studies on neutral lipids in excysted metacercariae and adults of E. trivolvis. Variations in the results of our study compared with others reflect intrinsic differences in the species of echinostome used.

Effects of Echinostoma caproni infection on the phospholipid and sphingolipid content of the intestinal mucosa of ICR mice

High performance thin layer chromatography (HPTLC) was used to determine phospholipids and sphingolipids in the intestinal mucosa of ICR mice infected with Echinostoma caproni for two weeks. The major phospholipids detected in both infected and non-infected mucosa were phosphatidylcholine (PC) and phosphatidylethanolamine (PE). HPTLC-densitometric analysis showed that there was a significant decrease in the weight of both PC and PE in the intestinal mucosa of infected mice compared to that of the uninfected controls. Cerebrosides and sulphatides, but not sphingomyelin, were identified in the intestinal mucosa of both infected and uninfected hosts. There was an apparent increase in the cerebroside content of the mucosa of infected versus control mice. The pathobiochemical changes seen in the polar lipid content of infected hosts probably reflect the feeding and behavioural activities of E. caproni in the mouse intestine.