Abstracts
2000 Digestive Disease Week

# 2217 Nitric Oxide Production by Kupffer Cells in Obstructive Jaundiced Rats: The Effect of Internal and External Drainage.
Wen Li, James Yw Lau, Danny Wh Lee, Enders Kw Ng, Angus Cw Chan, Joseph Jy Sung, Sydney Sc Chung, Hong Kong, P. R. China

Background: Nitric oxide, a small molecule that serves as a biological messenger, has been implicated in many disease processes. Its role in obstructive jaundice has not been extensively studied. Aims: To study nitrite production (as a measure of nitric oxide production) by Kupffer cells in experimental obstructive jaundice and the effect of internal and external drainage. Materials and Methods: Eighty male Sprague-Dawley rats weighing 300- 350 g were randomized into four groups: sham operation (SH, n=25), obstructive jaundice by bile duct ligation and division (OJ, n=25), internal drainage by choledochoduodenostomy (ID, n=15) and external drainage by exteriorizing a biliary drainage tube at the nape (ED, n = 15). Kupffer cells were isolated by in situ perfusion method with collagenase D as the digestive enzyme on day 7 in the SH and OJ groups and on day 14 (i.e. day 7 after drainage surgery) in the ID and ED groups. Kupffer cells were cultured with or without lipopolysaccharide (LPS, 100 ng/ml) as an activator respectively in 96-well plates. The nitrite productionin in cell culture supernatants was measured 48 hrs later using Greiss reagents. Results: There was no significant difference of nitrite production between the four groups without LPS stimulation (SH, 245.4±42.5; OJ, 234.4±46.2; ID, 168.3±34.3; ED, 313.1±98.6 nmol/mg protein)(P=0.489). When LPS was used as an activator, the nitrite production of Kupffer cells was significantly increased in OJ rats (698.5±101.3 nmol/mg) as compared with SH rats (275.2±49.8 nmol/mg) (P=0.001). After drainage procedures, the impaired Kupffer cell function was recovered by ID (270.5±46.4 nmol/mg) (P=0.007), but not by ED (502.7±114.0 nmol/mg) (P=0.769). Conclusion: Kupffer cells produce more nitric oxide in rats with obstructive jaundice. Internal biliary drainage depresses the generation of nitric oxide, but external drainage does not.