Members of the genus Trichinella are small nematodes that can infect a wide range of animal hosts. However, their infectivity varies depending on the parasite and host species combination. In this study, we examined the susceptibility of 4 species of laboratory rodents, i.e., mice, rats, hamsters, and gerbils to Trichinella papuae, an emerging non-encapsulated Trichinella species. Trichinella spiralis and Trichinella pseudospiralis were also included in this study for comparison. Fifteen animals of each rodent species were infected orally with 100 muscle larvae of each Trichinella species. Intestinal worm burden was determined at day 6 and 10 post-inoculation (PI). The numbers of muscle larvae were examined at day 45 PI. The reproductive capacity index (RCI) of the 3 Trichinella species in different rodent hosts was determined. By day 6 PI, 33.2-69.6% of the inoculated larvae of the 3 Trichinella species became adult worms in the small intestines of the host animals. However, in rats, more than 96% of adult worms of all 3 Trichinella species were expelled from the gut by day 10 PI. In gerbils, only 4.8-18.1% of adult worms were expelled by day 10 PI. In accordance with the intestinal worm burden and the persistence of adults, the RCI was the highest in gerbils with values of 241.5+/-41.0 for T. papuae, 432.6+/-48 for T. pseudospiralis, and 528.6+/-20.6 for T. spiralis. Hamsters ranked second and mice ranked third in susceptibility in terms of the RCI, Rats yielded the lowest parasite RCI for all 3 Trichinella species. Gerbils may be an alternative laboratory animal for isolation and maintenance of Trichinella spp.
Animals ; *Animals, Laboratory ; Cricetinae ; *Disease Susceptibility ; Gerbillinae ; Intestines/parasitology ; Male ; Mice ; Muscles/parasitology ; Parasite Load ; Rats ; Rodent Diseases/*parasitology/pathology ; Trichinella/*growth & development ; Trichinellosis/parasitology/pathology/*veterinary

OBJECTIVE: To evaluate the protective effect of excretory-secretory proteins from Trichinella spiralis muscle larvae (Ts-MES) on sepsis-induced myocardial injury in mice. METHODS: Eighty male BALB/C mice were randomized equally into sham-operated group, myocardial injury group, Ts-MES treatment group and dexamethasone treatment group. In the latter 3 groups, sepsis-induced myocardial injury models were established by cecal ligation and perforation; the sham operation was performed by exposure of the cecum without ligation or perforation. Forty minutes after the operation, the mice were given intraperitoneal injections 150 μL PBS, 20 μg TS-MES or 0.3 mg/kg dexamethasone as indicated. At 12 h after the operation, 6 mice were randomly selected from each group for echocardiography, and 8 mice were used for observing the survival rate within 72 h. The remaining 6 mice were examined for myocardial pathologies with HE staining and serum levels of NTPro-BNP and cTnI with ELISA; the expressions of TNF-α, IL-6, IL-10 and TGF-β in the serum and myocardial tissue were detected using ELISA and qRT-PCR. RESULTS: Compared with the sham-operated mice, the septic mice showed significantly decreased cardiac function indexes (LVEF, LVFS, and E/A) with lowered survival rate within 72 h (P < 0.001) and significantly higher myocardial injury scores and serum levels of NTPro-BNP and cTnI (P < 0.01). Treatment with TS-MES significantly improved the cardiac function and 72-h survival rate (P < 0.05) and lowered the myocardial injury scores and serum levels of NTPro-BNP and cTnI (P < 0.05) in the septic mice. Compared with the sham-operated mice, the septic mice had obviously increased TNF-α and IL-6 levels in the serum and myocardial tissue (P < 0.001), which were significantly lowered by treatment with TS-MES (P < 0.05). TS-MES and dexamethasone both increased the levels of IL-10 and TGF-β in the septic mice, but the changes were significant only in TS-MES-treated mice (P < 0.05). CONCLUSION Ts-MES are capable of protecting against myocardial injury in septic mice by reducing the production of pro-inflammatory cytokines and enhancing the levels of regulatory cytokines.
Animals ; Cytokines ; Dexamethasone ; Heart Injuries ; Interleukin-10 ; Interleukin-6 ; Larva ; Male ; Mice ; Mice, Inbred BALB C ; Myocardium ; Sepsis ; Transforming Growth Factor beta ; Trichinella spiralis ; Tumor Necrosis Factor-alpha