title: [In vitro killing of adult Trichinella spiralis by exogenous nitric oxide].
abstract: OBJECTIVE
  To investigate the lethal effect of exogenous nitric oxide on adult worms of Trichinella spiralis in vitro.
  
  
  METHODS
  Adult worms of T. spiralis isolated from the small intestine of Trichinella-infected BALB/c mice were cultured in RPMI 1640 medium with sodium nitroprusside (SNP) in different final concentration of 0, 0.02, 0.05, 0.10, 0.20, 0.50, and 1.00 mmol/L, 1.00 mmol/L SNP+0.15 mmol/L hemoglobin (Hb), 1.00 mmol/L SNP+0.15 mmol/L FeSO4, 1.00 mmol/L SNP+1.00 mmol/L L-cysteine (L-cyst), 1.00 mmol/L SNP+0.15 mmol/L FeSO4 +1.00 mmol/L L-cyst, respectively, and incubated at 37 degrees C in a humidified 5% CO2 atmosphere. On the 4th day after incubation, the adult worms were stained with safranin, and observed under light microscope. The worm mortality in the groups was analyzed.
  
  
  RESULTS
  Under concentration of 0.02 and 0.05 mmol/L, SNP was not cytotoxic to adult T. spiralis with an inhibition of (1.4 +/- 1.2)% and (3.2 +/- 1.0)%, respectively. The worm mortality in the groups of SNP 0.10, 0.20, 0.50, and 1.00 mmol/L was (9.9 +/- 1.8)%, (37.7 +/- 2.5)%, (50.1 +/- 3.5)%, and (80.8 +/- 1.1)%, respectively, significantly higher than that of negative control group [(1.9 +/- 0.2)%, P < 0.05]. There was a positive linear correlation between the worm mortality and SNP concentration in the range of 0.02-1.00 mmol/L. Combination of hemoglobin, L-cyst, FeSO4 and FeSO4+L-cyst with 1.00 mmol/L SNP led to a decrease of the mortality from (80.8 +/- 1.1)% to (56.5 +/- 3.7)%, (69.8 +/- 2.3)%, (74.8 +/- 2.4)%, (72.7 +/- 5.6)%, respectively.
  
  
  CONCLUSIONS
  Exogenous nitric oxide released from SNP can kill adult worms of Trichinella spiralis. However, hemoglobin and L-cysteine+FeSO4 can reverse its lethal effect on the parasites.
authors.affiliation: Departmennt of Microbiology and Parasitology, Benghu Medical College, Anhui Key Laboratory of Infection and Immunity, Bengbu 233030, China.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Wang
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Wang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Fang
authors.forename: Yu-Qin
authors.initials: YQ
authors.lastname: Xue
authors.forename: Ji-Long
authors.initials: JL
authors.lastname: Shen
mesh_terms: D000818:Animals; D003470:Culture Media; D003545:Cysteine; D005260:Female; D005296:Ferrous Compounds / Q000494:pharmacology; D006454:Hemoglobins; D007421:Intestine, Small / Q000469:parasitology; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D017160:Trichinella spiralis / Q000187:drug effects* / Q000302:isolation & purification; D014235:Trichinellosis / Q000469:parasitology*
chemical_list: D003470:Culture Media; D005296:Ferrous Compounds; D006454:Hemoglobins; D009599:Nitroprusside; D009569:Nitric Oxide; C020748:ferrous sulfate; D003545:Cysteine