US EPA

1700884 

Journal Article 

Effects of niacin on nitric oxide synthase expression in rat lungs exposed to silica 

Wang, SX; Du, HK; Zhang, XZ; Cai, SX; Fan, HQ; Wang, C 

2004 

1 

Progress in Natural Science
ISSN: 1002-0071 

14 

12 

1069-+ 

WOS:000225781100006 

The aim of this study was to evaluate the effects of niacin
in diet on the expression of nitric oxide synthase (NOS) in rat lungs of the animal model of
silicosis established by direct tracheal instillation of silica particles into rat lungs
surgically. The niacin concentration in serum was analyzed by high performance liquid
chromatography (HPLC). The expression of inducible nitric oxide synthase (iNOS) protein in
paraffin-embedded lung sections was determined by streptavidin/peroxidase (SP) staining.
Quantitative analysis by Image-Pro Plus was also performed on the expression of iNOS. The results
showed that niacin concentration in serum of the niacin-treated rats was significantly higher
than that in the control and silica-treated rats. After 7 days of silica instillation, iNOS
integrated optical density (IOD) in rat lungs and total NOS and iNOS activities in
bronchoalveolar lavage fluid (BALF) in silica-treated rats rose by 273420.75, 2.61 units/mL and
1.89 units/mL respectively, when compared with those in the control rats. Niacin treatment
significantly reduced silica-induced iNOS IOD in rat lung tissues and total NOS and iNOS
activities in BALF supernatant by 248292.35, 1.50 units/mL and 0.91 units/mL, respectively, as
compared with those in silica-treated rats. Therefore, niacin can effectively attenuate the
pathological expression of NOS in rat lung tissues induced by silica particles. 

niacin; silica; rat lung; nitric oxide synthase