In vitro evaluation of schistosomicidal potential of curcumin against Schistosoma japonicum.

Curcumin is a polyphenol derived from the dietary spice turmeric. The aim of this study was to investigate the in vitro effect of curcumin against eggs, cercariae, pre-adults, and adults of Schistosoma japonicum compared to praziquantel. After incubated by different concentration of curcumin or praziquantel in different time, the percent hatching rates of eggs, the percent dead rates of cercariae, and the number of dead worms were observed. Curcumin showed time- and dose-dependent schistosomicidal effects on every life stages of S. japonicum. In addition, curcumin exhibited an optimal activity against the adult stage with no differential sensitivity between male and female worms and decreased motor activity of these worms without tegumental alterations. The promising in vitro effects on all stages of S. japonicum warrants further evaluation for the prophylactic and therapeutic values in the early and late schistosomiasis in field trials.

[Schistosomicidal effect of BTW5 on adult and juvenile Schistosoma japonicum in vitro].

OBJECTIVE: To evaluate the killing effect of BTW5 on both juvenile and adult worms of Schistosoma japonicum in vitro. METHODS: The mice were infected with cercariae of Schistosoma japonicum obtained from infected Oncomelania hupensis. The juvenile worms were obtained from the liver and mesenteric veins of the mice by perfusion 18 d after the infection, and the adult worms were obtained from the liver and mesenteric veins of the mice by perfusion 5 weeks after the infection. The adult and juvenile worms were cultivated in DMEM medium containing different concentrations of BTW5 and were observed for 3 d. After the observation, the worms were stained by hydrochloric acid carmine to observe the injuries. RESULTS: The death rates and motility reducing rates of adult and juvenile worms in DMEM medium containing different concentrations of BTW5 were significantly higher than those in the controls. The staining suggested that BTW5 had a damage effect on the tegument and the intestinal canal of the male and female worms, in addition to the ovaries of the female worms. CONCLUSION: BTW5 has an antischistosomal effect on adult and juvenile worms of Oncomelania hupensis.

[Preliminary study on molluscicidal effect of Euphorbia helioscopia L ethanol extracts against Oncomelania hupensis].

OBJECTIVE: To study the influences of Euphorbia helioscopia L. on glycogen contents of Oncomelania hupensis so as to explore its molluscicidal mechanism. METHODS: The different polar factions of Euphorbia helioscopia L. were separated by using the systemic solvent segregation method, and then its molluscicidal activity was detected according to the Laboratory Final Milluscicides Screening Method issued by WHO. The glycogen contents of soft tissues of Oncomelania hupensis snails treated by Euphorbia helioscopia L. ethanol extracts were determined by the anthrone method. RESULTS: After being immersed for 48 h with Euphorbia helioscopia L. ethanol extracts, the death rates of the snails at the concentrations of 400 mg/L and 800 mg/L were 50.43% and 77.50% respectively, while after 96 h, the death rates at the above concentrations were both 100%. The glycogen contents of the snails gradually reduced with the increase of the drug concentrations, the glycogen content decreased to the lowest while the concentration was 800 mg/L, and the glycogen content decreased by 69.49% compared with that of the control group. CONCLUSION: The Euphorbia helioscopia L. ethanol extracts can significantly decrease the glycogen content of Oncomelania snails and the extracts have an adequate molluscicidal activity.

[Killing effect of sodium abietate on adult worms of Schistosoma japonicum in vitro].

OBJECTIVE: To observe the killing effect of sodium abietate on adult male and female worms of Schistosoma japonicum in vitro. METHODS: The mice infected with cercariae of S. japonicum were sacrificed and perfused five weeks later, the adult worms obtained by the portal perfusion method, were cultivated in DMEM medium containing different concentrations of sodium abietate for 3 days, except the controls, then the worms were observed for the death and motility reducing. The worms were stained by hydrochloric acid carmine for the detection of the changes, and the protein of the worms was detected by using the ultraviolet ray-absorption and Bradford method. RESULT: After the treatment of sodium abietate, the mortality and motility reducing rate of adult worms were higher significantly than the controls; the effect of sodium abietate on male worms was more obvious than on female worms. The male worms' intestinal canal enlarged and appeared black or brown bands or spots after the treatment. The contents of the intestine of female worms were distributed asymmetrically, and the shape of some worms' ovaries was anomalism and the coloring was asymmetrical. Compared with the control group, the protein of adult male and female worms were reduced (P < 0.05). CONCLUSION: Sodium abietate could kill adult worms of S. japonicum in vitro. It may affect the protein metabolism of the worms.

[Dynamic changes of early immune responses to attenuated Schistosoma japonicum cercariae induced in BALB/c mice].

OBJECTIVE: To study the early immune activation and its dynamic changes between the attenuated cercariae immunized mice and the normal infected mice. METHODS: The dendritic cell surface molecules CD11c and T cell surface molecule CD25 expression differences and CD3+CD25+/CD3+ T ratio of the early spleen and/or lung of the attenuated cercariae immunized mice and normal mice were assayed and compared by FCM and IHC, and the immune activation and dynamics of T cells were analyzed. RESULTS: CD3+CD25+CD3+ T ratio in the spleen cells 7 days post-infection in the immunized group and the normal infected group were (19.52 +/- 3.65)% and (22.12 +/- 3.24)%, respectively; the rates of 14 days and 21 days post-infection were (28.73 +/- 3.94)%, (13.68 +/- 3.64)% and(26.43 +/- 0.40)%, (14.42 +/- 2.24)%, respectively. The expressions of CD11c+DC in the lung of the two groups were (1.05 +/- 0.16)%, (0.96 +/- 0.15)%, (1.34 +/- 0.15)%, (1.09 +/- 0.17)%, (1.49 +/- 0.14)%, (0.97 +/- 0.16)%, respectively; the expressions in the spleen were (2.05 +/- 0.26)%, (1.95 +/- 0.18)%, (2.24 +/- 0.25)%, (2.17 +/- 0.25)%, and (2.18 +/- 0.26)%, (2.06 +/- 0.18)%, respectively, on the 7, 14 and 21 days post-infection. The expressions of CD25+T cells in the lung of the two groups were (1.24 +/- 0.13)%, (1.17 +/- 0.16)%, (1.48 +/- 0.11)%, (1.25 +/- 0.13)%, and (1.55 +/- 0.14)%, (0.97 +/- 0.12)%, respectively; the expressions in the spleen were (3.25 +/- 0.22)%, (2.93 +/- 0.20)%, (4.57 +/- 0.23)%, (3.69 +/- 0.24)% and (4.28 +/- 0.24)%, (3.86 +/- 0.26)%, respectively, on the 7, 14 and 21 days post-infection. The CD3+CD25+/CD3+T rate in the infection control group was significantly higher than that in the cercariae attenuated group, while 14, 21 days post-infection the rates of the attenuated group were significantly higher than those in the normal control group. On the 7, 14 and 21 days post-infection, the lung tissue of the attenuated cercariae immunized mice raised more CD11c+ DC and CD25+ T cells than that of the normal infected mice did. CONCLUSIONS: The activation of T cells of the immune group and the activation of pulmonary dendritic cells are higher than those in the control group 7 and 14 days post-infection, suggesting that attenuated cercariae in the lungs can raise more antigen presenting cells and their activation.