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Background: The maternal-fetal infection/inflam-mation is believed to be the mechanism in the patho-genesis of periventricular leukomalacia (PVL). The activation of microglias (MGs) may contribute to preoligodendroglial damage. The present study was undertaken to explore the effect of N-[3-(aminomethyl) benzyl] acetamidine (1400W), a selective inhibitor of inducible nitric oxide synthase (iNOS), on the blockage of lipopolysaccharide (LPS)-induced microglial toxicity to preoligodendrocytes (preOLs).
Methods: The co-cultural MGs and preOLs obtained from two-day-old Sprague-Dawley (SD) neonatal rats were divided into three groups: co-culture control group, co-culture LPS group, and co-culture LPS plus 1400W group. The concentration of nitric oxide (NO) was measured by nitric acid-deoxidize-colorimetry, the level of peroxynitrite (ONOO¨C) determined by immunocytochemistry, the synthetic level of inducible nitric oxide synthase (iNOS) detected by western blotting, and the apoptotic rate of preOLs assessed by flow cytometry after the co-cultural cells were induced by LPS (100 ng/ml) for 48 hours.
Results: Compared with those in the co-culture control group, the levels of NO (82.27¡À3.41 ¦Ìmol/L vs. 167.86¡À9.87 ¦Ìmol/L, P<0.01), ONOO¨C (6.14¡À1.27 vs. 34.38¡À7.75, P<0.01), and iNOS (0.18¡À0.027 vs. 0.79¡À0.068, P<0.01) induced by LPS increased remarkably in the co-culture LPS group, with a higher apoptotic rate of preOLs (6.73¡À1.39% vs. 24.77¡À2.05%, P<0.01). The levels of NO (69.55¡À5.07 µmol/L, P<0.01), ONOO¨C (10.33¡À3.47, P<0.01) and iNOS (0.35¡À0.042, P<0.01) were decreased significantly using 1400W at a dose of 10 µmol/L in the co-culture LPS plus 1400W group, and the apoptotic rate of preOLs (11.80¡À2.06% vs. 24.77¡À2.05%, P<0.01) also decreased compared with the co-culture LPS group.
Conclusion: 1400W can block effectively the LPS-induced microglial toxicity to preOLs by inhibiting iNOS specifically, resulting in a significant reduction of toxicity parameters investigated and a marked increase of the survival preOLs.
Key words: N-[3-(aminomethyl) benzyl] acetamidine; inducible nitric oxide synthase; nitric oxide; peroxynitrite; preoligodendrocyte
World J Pediatr 2010;6(3):249-254
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