Mechanism Of ω-3Fish Oil Improving Parenteral Nutrition-Associated Liver Disease And Its Endoplasmic Reticulum Stress

Objective：By establishing parenteral nutrition-associated liver disease (PNALD) model innewborn rabbits,to study the expression changes of endoplasmic reticulum stresschaperone protein-glucose regulatory protein94(GRP94) in PNALD, to explore the roleof the GRP94in the pathogenesis of PNALD and reveal the mechanism on the ω-3fish oilhow to improve PNALD and so as to provide the experimental basis for clinical preventionand treatment of PNALD.Materials and Methods:Twenty-four newborn New Zealand rabbits, either male or female, breast-fed for7days, were randomly divided into three groups:8for control group (CON group),8for totalparenteral nutrition group (TPN group), and8for ω-3fish oil fat emulsion interventiongroup (FO group).The TPN group received continuous total parenteral nutrition through asilatic catheter inserted in the right jugular vein for one week; ω-3fish oil fat emulsion inthe FO group replaced the ordinary fat emulsion in the TPN nutrition by equivalent;theCON group received breast-feeding for one week. All rabbits raised in constanttemperature warm box with temperature between26-28℃and relative humidity between40%-60%. The fluid volume was based on body weight according to240ml·kg-1·d-1. Serumbiochemistry indicators were tested; liver histological examitations of three groups wereperformed by henatoxylin-eosin staining; GRP94mRNA were detected bysemi-quantitative reverse transcription polymerase chain reaction (RT-PCR).Immunohistochemistry was used to test GRP94proteinResults:1. The level of serum biochemical indexes: on the levels of TBIL, DBIL, γ-GT andALB, there were significant differences among the three groups (P <0.01). However, onthe levels of TP, ALT, AST, ALP, TG, TC and PA, there were no significant differencesamong the three groups (P>0.05). The TPN group had an obvious elevation of TBIL (50.25 ±3.06)μmol/Lνs (2.28±1.04) μmol/L, DBIL (47.28±3.91) μmol/L νs (1.05±0.57)μmol/L, γ-GT (130.47±5.61) IU/L νs (14.33±5.46) IU/L compared with CON group,and the difference was statistically significant (P<0.01). While, the ALB (11.73±1.05) g/Lνs (26.86±2.83) g/L significantly reduced, the difference was statistically significant(P<0.01). There were no significant differences in TBIL (3.28±1.69) μmol/Lνs (2.28±1.04) μ mol/L, DBIL (1.76±0.86) μmol/Lνs (1.05±0.57) μ mol/L, γ-GT (14.33±5.45)IU/Lνs (11.28±5.68) IU/L, and ALB (26.29±3.12) g/Lνs (26.86±2.83) g/L betweenCON group and FO group(P>0.05). Compared with TPN group,TBIL (3.28±1.69)μmol/Lνs (50.25±3.06)mol/L, DBIL(1.76±0.86) μmol/Lνs (47.28±3.91) μmol/L,γ-GT (14.33±5.45) IU/Lνs (130.47±5.61) IU/L in FO group were significantly decreased,the differences were statistically significant (P <0.01), ALB (26.29±3.12) g/Lνs(11.73±1.05)g/L was significantly increased, the difference was statistically significant (P <0.01).2. Comparision of henatoxylin-eosin staining in the liver of three newborn rabbitgroups: Compared with CON group, the liver tissue in TPN group shows hepatic steatosis,inflammation cells infiltration, but no significant bile duct proliferation and cholestasis.While the FO group is only visible to a small number of liver steatosis, there was a smallamount of inflammatory cell infiltration.3. Expression of Endoplasmic reticulum stress marker protein-GRP94protein: Theimmunohistochemistry results showed that protein expression of GRP94in the liver ofTPN group was significantly increased compared with CON group (133.838±13.664νs78.138±8.169)(P <0.01), FO group’s was no significant difference compared with CONgroup (80.727±9.356νs78.138±8.169)(P>0.05). But, the FO group’s significantlyreduced compared with TPN group(80.727±9.356νs133.838±13.664)(P <0.01).4. Expression of Endoplasmic reticulum stress marker protein-GRP94mRNA: Theresults in RT-PCR showed that the expression of GRP94mRNA in the liver of TPN groupwas significantly increased compared with CON group (1.217±0.113νs0.614±0.034)(P<0.01). FO group’s was no significant difference compared with CON group (0.661±0.117νs0.614±0.034)(P>0.05), but FO group’s significantly reduced compared withTPN group (0.661±0.117νs1.217±0.113)(P <0.01).Conclusion:1. In this study, we successfully established parenteral nutrition-associated liver disease model, and set the basis for further studies of its pathogenesis.2. The expression of GRP94in the TPN group was significantly increased comparedwith CON group, endoplasmic reticulum stress may be directly related to the occurrenceand development of TPN-related liver disease.3. ω-3fish oil fat emulsion alternative to ordinary fat emulsion can be effective inimproving the TPN-induced liver dysfunction, and it may be play an important role in theinhibition expression of the endoplasmic reticulum stress protein-GRP94.