Apoptosis and caspase-3 in long-term renal ischemia/reperfusion injury in rats and divergent effects of immunosuppressants.
BACKGROUND
Caspase-3 plays a key role in apoptosis, but the involvement of apoptosis and caspase-3 in mediating long-term ischemia/reperfusion (I/R) and immunosuppressive injury are not fully defined. The present study was undertaken to investigate apoptosis and caspase-3 in a renal I/R injury rat model with or without immunosuppression.


METHODS
The right renal pedicle was clamped for 45 minutes and left nephrectomy was induced. Cyclosporin A (CsA), tacrolimus (Tac), rapamycin (Rap), or mycophenolate mofetil (MMF) were administered daily. Animals were killed at 16 weeks, and the levels of apoptosis (with in situ end-labeling fragmented DNA), caspase-3 protein (with immunohistochemistry, Western blotting, and activity assay), and messenger RNA (mRNA; with quantitative reverse-transcriptase polymerase chain reaction) were evaluated.


RESULTS
Kidneys with I/R injury showed increased apoptosis in tubular and interstitial areas compared with control kidneys. Tacrolimus, Rap, and MMF significantly reduced apoptosis, but CsA did not. Distribution of full-length caspase-3 widened in I/R-injured kidneys from normal distal tubules and collecting ducts to dilated proximal tubules and expanded interstitium, whereas active caspase-3 was mainly scattered in damaged tubules and interstitium. Active caspase-3 staining and 24-kDa active caspase-3 protein was enhanced in I/R-injured and CsA-treated kidneys, but decreased by Tac, Rap, and MMF. These results were also consistent with changes in caspase-3 activity. Although caspase-3 mRNA levels were significantly increased in uninephrectomy and I/R-injured kidneys, they were not significantly affected by the immunosuppressants. In addition, all changes detected were positively correlated with renal structure and function.


CONCLUSIONS
Apoptosis and caspase-3 are not only involved in the long-term renal I/R injury, but also mediate the divergent effects of immunosuppression in this model.
Yang
Bin
B
Department of Infection, Immunity and Inflammation, University of Leicester, Leicester General Hospital, UK. by5@le.ac.uk
Jain
Sunjay
S
Ashra
Shairbanu Y
SY
Furness
Peter N
PN
Nicholson
Michael L
ML
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000187:drug effects / Q000378:metabolism*; D015870:Gene Expression; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007668:Kidney / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D016030:Kidney Transplantation / Q000009:adverse effects; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000503:physiopathology*
D007166:Immunosuppressive Agents; D012333:RNA, Messenger; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases