Estimation of nitric oxide level in mice infected by trichinella spiralis

ABSTRACT

Trichinella spiralis infection causes intestinal inflammation that is associated with hypermotility and hypersecretion. Nitric oxide [NO] is a major secretory product of mammalian cells, with a critical role in host non-specific defense, and has been identified as an important effector molecule that can play a role in immuno-regulation. To investigate the role of NO and the changes in its level in experimental Trichinella spiral/s infection. 150 mice of both sexes were divided into five groups. GI served as healthy control [uninfected untreated group]. The other four groups were infected each with 250 larvae/mouse, G2 served as infected untreated control group, G3 was infected and administered NO in the form of 1 mg/kg intraperitoneally of glycerile trinitrate [Nitrocine], G4 was infected and administered nitric oxide synthase inhibitor in the form of 3 mg/kg intraperitoneally of L-NAME, and G5 was infected and treated with both Nitrocine and L-NAME. Drugs were given three times weekly from day 3 to day 28 post-infection. Two stable breakdown products, nitrate [NO3] and nitrite [NO,] were detected and determined at weekly intervals for 14 weeks for Gl and G2, and at the end of the 14th week in the other three groups, hence NO was calculated. Adult and larval counts were measured in each mouse with estimation of NO, and NO, levels. The adult worm count on the 7th day was 95.2 +/- 3.1 in G2; 142.12+2.94 in G3; 88.3+3.61 in G4 and 107.57+4.03 in G5, while on the 14th day [intestinal and migratory phase], the count was zero in all different groups. The larval count/diaphragm muscle was 690.15+108.1, 1261.75+244.7, 547.3 +/- 130.1 and 1089.0+107.7 in G2. G3. G4 and G5 respectively. Significant increases in NO levels were observed in G3 and G5 compared to G2 and G4 with peak serum level at week 9 in G2. Conclusion: NO administered as a drug intensified T spiralis infection and inhibition of the effect of NO by L-NAME reduced the numbers of worms and larvae. Further studies are needed to determine pro and anti-inflammatory effects of NO on different parasitic infections and the relationship between NO function and concentration in the microenvironment of inflammatory lesions