Evaluation of the uptake function of liver in rats with obstructive jaundice before and after relief from obstruction by superparamagnetic iron oxide-enhanced magnetic resonance imaging

Monitoring of impaired phagocytic function of Kupffer cells in an obstructive cholangitis rat model using superparamagnetic iron oxide MRI and contrast-enhanced ultrasound

BACKGROUND

Kupffer cells (KC) have an important role in the host defense in obstructive cholangitis. Non-invasive monitoring of phagocytic function of KC is pivotal. Several studies showed the possibility of non-invasive monitoring of phagocytic function of KC using superparamagnetic iron oxide-enhanced magnetic resonance imaging (SPIO-MRI) or contrast-enhanced ultrasound (CEUS).

PURPOSE

To investigate the serial change of KC function using SPIO-MRI and CEUS and whether the SPIO-MRI parameter correlates with the CEUS parameter in obstructive cholangitis rat models.

MATERIAL AND METHODS

With our institutional Animal Care and Use Committee approval, 19 rats (common bile duct ligation [CBDL]: n = 9; control: n = 10) underwent SPIO-MRI and CEUS at baseline, two, and four weeks after CBDL. The relative signal loss (RSL) of T2* value on SPIO-MRI and Kupffer phase parenchymal echogenicity (KPE) on CEUS were measured. The correlation between SPIO-MRI and CEUS parameters were compared with KC count.

RESULTS

In CBDL group, RSL and KPE had significantly decreased (72.1% to 29.5%, 2.7 to 0.4) at four weeks compared with those in the control group (68.2% to 58.3%, 2.5 to 3.0, P < 0.05). During the follow-up period, RSL showed significantly positive correlations with KPE ( P = 0.007). In addition, at four weeks, we found RSL was positively correlated with KPE (ρ = 0.750, P = 0.002). KC count was negatively correlated to RSL and KPE at four weeks (ρ = -0.771, P = 0.001 and ρ = -0.644, P = 0.013).

CONCLUSION

SPIO-MRI and CEUS may be equally useful for monitoring the serial changes of KC phagocytic function in vivo.

A simple rat model of in situ reversible obstructive jaundice in situ reversible obstructive jaundice model

PURPOSE

To develop a simple and reliable rat model of in situ reversible obstructive jaundice with low morbidity and mortality rates.

METHODS

Rats were divided into 4 groups with 8 rats each: the sham-operated (SH) group only underwent laparotomy, the control internal drainage (ID-C) group underwent choledochoduodenostomy, the new internal drainage (ID-N) group and the long-term internal drainage (ID-L) group underwent choledochocholedochostomy. Common bile duct ligation was performed in all the drainage groups 7 days before reversal procedures. All rats were sacrificed for samples 7 days after the last operation except rats of the ID-L group that survived 28 days before sacrifice. Body weight, liver function, histopathological changes, morbidity and mortality were assessed.

RESULTS

One rat died and 2 rats had complications with tube blockage in the ID-C group. No death or complications occurred in the ID-N and ID-L groups. The drainage tube remained patent in the long-term observation ID-L group. Body weight showed no significant difference between the ID-C and ID-N groups after 7 days drainage. Liver function was not fully recovered in the ID-C and ID-N groups after 7 days drainage, but statistical differences were only observed in the ID-C group compared with the SH and ID-L groups. Periportal inflammation and bile duct proliferation showed severer in the ID-C group than in the ID-N group.

CONCLUSION

The present study provided an efficient, simple, and reliable rat model that is especially suitable for long-term or consecutive studies of reversible obstructive jaundice.