Erythropoietin Attenuates Lipopolysaccharide-Induced Splenic and Thymic Apoptosis in Rats

T. F. KOROGLU¹, O. YILMAZ², E. OZER³, H. BASKIN⁴, N. GOKMEN⁵,
A. KUMRAL¹, M. DUMAN¹, H. OZKAN<sup>1

1</sup>Department of Pediatrics, ²Animal Research Laboratory, ³Department of Pathology, ⁴Department of Microbiology, ⁵Department of Anesthesiology, Dokuz Eylul University School of Medicine, Izmir, Turkey

Received April 4, 2005
Accepted July 5, 2005
On-line available August 5, 2005


Summary
Apoptosis of lymphoid tissues during sepsis is well documented and linked to the pathobiology of organ failure and death. In this study, we evaluated the effect of a single dose of recombinant erythropoietin (EPO) on thymic and splenic apoptosis in an endotoxic sepsis model. Young male Wistar rats were divided into 3 groups and administered intraperitoneally (IP) either normal saline; lipopolysaccharide (LPS) 10 mg/kg; or EPO (5000 U/kg) 30 min before lipopolysaccharide. Six hours following LPS administration animals were sacrificed. Apoptosis was assessed by hematoxylin-eosin staining, terminal deoxynucleotide transferase-mediated fluorescein-dUTP nick end labeling (TUNEL), and caspase-3 immunostaining. When compared with animals given LPS, animals pretreated with EPO displayed reduced splenic and thymic TUNEL positivity of 44±3 (p<0.05) and 1434 (p<0.05) nuclei per high power field (hpf), respectively. Caspase-3 positivity was also significantly reduced in the spleen and thymus, with 31±4 (p<0.05) and 93±3 (p<0.05) positive stained nuclei per hpf, respectively. Serum nitrite levels were elevated in animals given lipopolysaccharide. Pretreatment with EPO attenuated the increase in nitrite levels; however, this did not reach statistical significance. We conclude that a single dose of recombinant erythropoietin can reduce thymic and splenic apoptosis associated with lipopolysaccharide administration.


Key words
Sepsis • Endotoxin • Lymphocyte • Erythropoietin