Deficiency of inducible nitric oxide synthase exacerbates hepatic fibrosis in mice fed high-fat diet.
The role of inducible nitric oxide synthase (iNOS) in the progression of fibrosis during nonalcoholic steatohepatitis remains to be elucidated. This study examined the role of iNOS in the progression of fibrosis during steatohepatitis by comparing iNOS knockout (iNOS(-/-)) and wild-type (iNOS(+/+)) mice that were fed a high-fat diet. Severe fatty metamorphosis developed in the liver of iNOS(+/+) and iNOS(-/-) mice. Fibrotic changes were marked in iNOS(-/-) mice. Gelatin zymography showed that pro MMP-2 and pro MMP-9 protein expressions were more highly induced in iNOS(+/+) mice than in iNOS(-/-) mice. Active forms of MMP-2 and MMP-9 were clearly present only in the liver tissue of iNOS(+/+) mice. In situ zymography showed strong gelatinolytic activities in the liver tissue of iNOS(+/+) mice, but only spotty activity in iNOS(-/-)mice. iNOS may attenuate the progression of liver fibrosis in steatohepatitis, in part by inducing MMP-2 and MMP-9 expression and augmenting their activity.
Chen
Yi
Y
Department of Physiology, School of Medicine, Tokai University, Bohseidai, Isehara, Kanagawa 259-1193, Japan.
Hozawa
Shigenari
S
Sawamura
Sadaaki
S
Sato
Shinkichi
S
Fukuyama
Naoto
N
Tsuji
Chizuko
C
Mine
Tetsuya
T
Okada
Yasunori
Y
Tanino
Ryuzaburo
R
Ogushi
Yoichi
Y
Nakazawa
Hiroe
H
D000818:Animals; D004041:Dietary Fats / Q000378:metabolism*; D005234:Fatty Liver / Q000150:complications / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008103:Liver Cirrhosis / Q000209:etiology / Q000378:metabolism*; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019001:Nitric Oxide Synthase / Q000172:deficiency*; D052247:Nitric Oxide Synthase Type II; D011347:Procollagen / Q000378:metabolism*; D012720:Severity of Illness Index
D004041:Dietary Fats; D011347:Procollagen; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D020782:Matrix Metalloproteinases