Effects of praziquantel isomers on the proliferation and activation of the LX-2 human hepatic stellate cell line / 中国血吸虫病防治杂志

Objective To compare the effects of levo-praziquantel (L-PZQ) and dextro-praziquantel (D-PZQ) on the proliferation and activation of the human hepatic stellate cell line LX-2 in vitro. Methods LX-2 cells were stimulated with transforming growth factor-β (TGF-β). LX-2 cell proliferation was measured using the CCK-8 assay after 24 h stimulation with 0 to 50 μg/mL concentrations of praziquantel, and the gene and protein expression of type Ⅰ collagen (collagen Ⅰ), type Ⅲ collagen (collagen Ⅲ) and α-smooth muscle actin (α-SMA) was quantified in LX-2 cells using quantitative real-time PCR (qPCR) and Western blotting assays 24 h and 48 h following stimulation with 15 μg/mL praziquantel to detect LX-2 cell activation. Results There were significant differences in the survival rate of LX-2 cells between L-PZQ and D-PZQ treatments at all concentrations (F = 6.119 and 79.180, both P values < 0.05). Either L-PZQ or D-PZQ at a concentration of < 30 μg/mL showed no remarkableeffectsonthe LX-2 cell proliferation (both P values > 0.05), and L-PZQ at a concentration of > 50 μg/mL and D-PZQ at a concentration of > 40 μg/mL inhibited the LX-2 cell proliferation (both P values < 0.05), while D-PZQ at concentrations of 40 μg/mL and 50 μg/mL showed greater inhibition on LX-2 cell proliferation than L-PZQ (t = 3.419 and 8.776, both P values < 0.05). There were significant differences in the collagen Ⅰ, collagen Ⅲ and α-SMA expression in LX-2 cells at both transcriptional (F = 21.55, 79.99 and 46.70, all P values < 0.05) and translational levels (F = 20.12, 30.29 and 32.93, all P values < 0.05) among the blank control group, TGF-β stimulation group, L-PZQ treatment group and D-PZQ treatment group. L-PZQ treatment resulted in remarkable inhibition on collagen Ⅲ and α-SMA gene expression in LX-2 cells (both P values < 0.05); however, the treatment showed no remarkable inhibition collagen Ⅰ gene expression or collagen Ⅰ, collagen Ⅲ or α-SMA protein expression in LX-2 cells (all P values > 0.05). In addition, D-PZQ treatment resulted in significant inhibition on collagen Ⅰ, collagen Ⅲ and α-SMA expression in LX-2 cells at both translational and transcriptional levels (all P values < 0.05), and D-PZQ showed higher inhibition on collagen Ⅰ, collagen Ⅲ and α-SMA gene expression in LX-2 cells than L-PZQ (all P values < 0.05). Conclusions Both L-PZQ and D-PZQ inhibit the proliferation and activation of LX-2 cells, and D-PZQ shows a higher inhibitory activity than L-PZQ.

Molluscicidal activity of the secondary metabolites from Streptomyces nigrogriseolus XD 2-7 against Oncomelania hupensis and its preliminary mechanisms of molluscicidal actions / 中国血吸虫病防治杂志

OBJECTIVE@#To evaluate the storage stability of metabolites from actinomycetes Streptomyces nigrogriseolus XD 2-7 and the mollcuscicidal activity against Oncomelania hupensis in the laboratory, and to preliminarily explore the mechanisms of the molluscicidal activity.@*METHODS@#The fermentation supernatant of S. nigrogriseolus XD 2-7 was prepared and stored at -20, 4 °C and 28 °C without light for 10 d; then, the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The fermentation supernatant was boiled in a 100 °C water bath for 30 min and recovered to room temperature, and then the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The pH values of the fermentation supernatant were adjusted to 4.0, 6.0 and 9.0 with concentrated hydrochloric acid and sodium hydroxide, and the fermentation supernatant was stilled at room temperature for 12 h, with its pH adjusted to 7.0; then, the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The fermentation product of S. nigrogriseolus XD 2-7was isolated and purified four times with macroporous resin, silica gel and octadecylsilane bonded silica gel. The final products were prepared into solutions at concentrations of 10.00, 5.00, 2.50, 1.25 mg/L and 0.63 mg/L, and the molluscicidal effect of the final productswas tested against O. hupensis following immersion for 72 h, while dechlorination water served as blank controls, and 0.10 mg/L niclosamide served as positive control. The adenosine triphosphate (ATP) and adenosine diphosphate (ADP) levels were measured in in O. hupensis soft tissues using high performance liquid chromatography (HPLC) following exposure to the final purified fermentation products of S. nigrogriseolus XD 2-7.@*RESULTS@#After the fermentation supernatant of S. nigrogriseolus XD 2-7 was placed at -20, 4 °C and 28 °C without light for 10 d, immersion in the stock solution and solutions at 10- and 50-fold dilutions for 72 h resulted in a 100% (30/30) O. hupensis mortality. Following boiling at 100 °C for 30 min, immersion in the stock solution and solutions at 10- and 50-fold dilutions for 72 h resulted in a 100.00% (30/30) O. hupensis mortality. Following storage at pH values of 4.0 and 6.0 for 12 h, immersion in the fermentation supernatant of S. nigrogriseolus XD 2-7 for 72 h resulted in a 100.00% (30/30) O. hupensis mortality, and following storage at a pH value of 9.0 for 12 h, immersion in the fermentation supernatant of S. nigrogriseolus XD 2-7 for 72 h resulted in a 33.33% (10/30) O. hupensis mortality (χ2 = 30.000, P < 0.05). The minimum concentration of the final purified fermentation products of S. nigrogriseolus XD 2-7 was 1.25 mg/L for achieving a 100% (30/30) O. hupensis mortality. The ATP level was significantly lower in O. hupensis soft tissues exposed to 0.10 mg/L and 1.00 mg/L of the final purified fermentation products of S. nigrogriseolus XD 2-7 than in controls (F = 7.274, P < 0.05), while no significant difference was detected in the ADP level between the treatment group and controls (F = 2.485, P > 0.05).@*CONCLUSIONS@#The active mollcuscicidal ingredients of the S. nigrogriseolus XD 2-7 metabolites are maintained stably at -20, 4 °C and 28 °C for 10 d, and are heat and acid resistant but not alkali resistant. The metabolites from S. nigrogriseolus XD 2-7 may cause energy metabolism disorders in O. hupensis, leading to O. hupensis death.

Activity of aromatic pyrrole-based compounds against of Schistosoma japonicum cercariae and acute toxicity to fish / 中国血吸虫病防治杂志

Objective To test the activity of aromatic pyrrole-based compounds against cercariae of Schistosoma japonicum and test their acute toxicity to fish. Methods A series of aromatic pyrrole-based compounds were synthesized using 4-benzyl-5-(trifluoromethyl)-1H-pyrrole-3-nitrile as the lead compound. The synthesized compounds were prepared into solutions at concentrations of 10.00, 1.00, 0.10, 0.01 mg/L, and the activity of these solutions against S. japonicum cercariae was tested in 30 min, while 0.10 mg/L and 0.01 mg/L niclosamide solutions served as a positive control and dechlorinated water with 1% dimethyl sulfoxide (DMSO) was used as a negative control, with 10 to 30 cercariae of S. japonicum in each group. In addition, the compounds were prepared into solutions at concentrations of 0.50, 0.25, 0.12, 0.06, 0.03 mg/L, and their toxicity to zebrafish was tested in 72 h, while 0.15 mg/L and 0.30 mg/L niclosamide solutions served as a positive control and dechlorinated water with 1% DMSO was used as a negative control, with 10 zebrafishes in each group. Results A total of 7 aromatic pyrrole-based compounds were successfully synthesized. Treatment with compounds 102, 104 and 106 at a concentration of 0.01 mg/L for 30 min killed all S. japonicum cercariae, and compounds 105 and 107 showed no activity against cercariae. No death of cercariae was found in the blank control group, while treatment with 0.10 mg/L niclosamide for 10 min caused a 100% mortality rate of S. japonicum cercariae and 0.01 mg/L niclosamide failed to kill S. japonicum cercariae. No zebrafish death was found 72 h post-treatment with compounds 101, 104 and 105 at a concentration of 0.03 mg/L, and exposure to compounds 102, 103 and 106 at a concentration of 0.03 mg/L for 12 h resulted in a 100% mortality rate of zebrafish. No zebrafish death occurred 72 h post-treatment with 0.50 mg/L Compound 104, and no zebrafish death was found in the blank control group, while treatment with 0.30 mg/L niclosamide for 24 h resulted in a 100% mortality rate of zebrafish. Conclusions Compound 104 achieves a 100% mortality rate against S. japonicum cercariae at a concentration of 0.01 mg/L for 30 min, and causes no death of zebrafish at a concentration of 0.50 mg/L for 72 h, which may serve as a cercaricide candidate.