Immunomodulation of hepatic ischemic injury via increased Bcl-X(L) and decreased Bcl-X(S).
BACKGROUND
Although classic ischemia-reperfusion injury is mediated by reactive oxygen intermediaries, increasing evidence implicates a role for immune-mediated apoptosis during ischemic injury in transplantation. Herein, we report the effects of polyclonal rabbit anti-thymocyte globulin (rATG) on mediators of hepatic apoptosis during cold storage.


METHODS
Three-month-old male Lewis rats were placed under halothane anesthesia and the portal vein cannulated. University of Wisconsin (UW) solution (35 ml) with (n = 5) and without (n = 5) 20 mg/kg anti-rat rATG was infused before hepatectomy. The liver was stored in UW solution +/- rATG (143 ng/ml) at 4 degrees C for various times up to 24 h. Specimens were terminal deoxyuridine nick end labeling-stained for apoptosis. Tissue lysates were analyzed by Western blotting and densitometry.


RESULTS
Compared to UW alone, significantly fewer apoptotic cells were present in UW + rATG perfused and stored livers. There were early and sustained significant increases in Bcl-X(L) and decreases in Bcl-X(S) with rATG. There was an initial, but not sustained, significant decrease in Bax with rATG. Moreover, there was a significant one-third decrease in caspase-9 production with rATG at 0, 6, 12, and 18 h.


CONCLUSIONS
Decreased proapoptotic Bcl-X(S) and increased antiapoptotic Bcl-X(L), as well as decreased downstream proapoptotic caspase-9 expression, during liver ischemia after treatment with rATG, all favor cell survival. Because apoptotic ischemic injury results in allograft dysfunction, preservation strategies that ameliorate such immunological effects may improve organ function.
Woodside
Kenneth J
KJ
Department of Surgery, The University of Texas Medical Branch, Galveston, Texas, USA.
Song
Juquan
J
Song
Wei
W
Hu
Mingdao
M
Meng
Tao
T
Hunter
Glenn C
GC
Wolf
Steven E
SE
Daller
John A
JA
D000241:Adenosine / Q000494:pharmacology; D000276:Adjuvants, Immunologic / Q000378:metabolism*; D000493:Allopurinol / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D003080:Cold Temperature; D005978:Glutathione / Q000494:pharmacology; D007136:Immunoglobulins / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D008099:Liver / Q000276:immunology / Q000378:metabolism*; D016031:Liver Transplantation; D008297:Male; D009926:Organ Preservation; D019188:Organ Preservation Solutions; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D011887:Raffinose / Q000494:pharmacology; D051381:Rats; D011917:Rats, Inbred Lew; D015427:Reperfusion Injury / Q000276:immunology / Q000378:metabolism* / Q000517:prevention & control; D051020:bcl-X Protein
D000276:Adjuvants, Immunologic; C494813:Bcl2l1 protein, rat; D007136:Immunoglobulins; D007328:Insulin; D019188:Organ Preservation Solutions; D019253:Proto-Oncogene Proteins c-bcl-2; C055206:University of Wisconsin-lactobionate solution; D051020:bcl-X Protein; D000493:Allopurinol; C506435:Casp9 protein, rat; D053453:Caspase 9; D020169:Caspases; D005978:Glutathione; D000241:Adenosine; D011887:Raffinose