P-31 NUCLEAR-MAGNETIC-RESONANCE STUDY OF PHOSPHOLIPIDS IN ISCHEMIA REPERFUSION INJURY IN A RAT FATTY LIVER MODEL/

Obese Zucker rats are susceptible to increased hepatic ischemia/reperf usion (I/RP) injury. Increased lipid peroxidation occurs in this model with warm ischemia. We hypothesized that a severe depletion of phosph olipids (PL) occurs with warm I/RP in fatty livers. Obese (Ob) and lea n (Ln) Zucker rats were subjected to 90 min of in vivo partial hepatic warm I followed by RP. Total lipids extracted from one gm of liver (m edian lobe) taken at the end of I, 2 and 6 hr of RP and sham (Sh) surg ery (n=5 Ln & Ob) were analyzed by 202.3 MHz P-31 NMR, which provided good resolution of individual FL. Obese (Sh) rats contained 22% more P L than Ln (P=<0.01). Ischemia caused similar decreases in PL in both O b (to 67% Sh) and Ln rats (62%). Following 2 hr RP, PL in Ob rats decr eased further (46% Sh) and recovered only marginally at 6 hr (53%), in marked contrast to the rapid recovery in Ln to preischemic levels (11 0% Sh at both 2 and 6 hr; P=<0.001). Mole percents of individual PL di d not change significantly except for lysophosphatidylcholine, which i ncreased from 0.43 to 1.3% (Sh vs. 6 hr RP) in the Ob, but decreased f rom 0.98 to 0.52% in Ln animals (P=<0.001). Fatty livers thus are more vulnerable to phospholipid depletion in response to warm ischemia/rep erfusion than normal livers.