RESUMO
Renal ischemia-reperfusion injury (IRI) is commonly encountered in clinical practice during renal transplantation. In a trial to find the drug that best safeguards the kidney against IRI, dexamethasone (Dex), N-acetyl cysteine (NAC), and theophylline (Theo) were tested in experimental rat models. This study included 105 adult male albino rats, which were randomly assigned to the following five groups: Group I - sham-operated, n = 5, Group II - IRI n = 25, Group III - IRI + Dex n = 25, Group IV - IRI + NAC n = 25, and Group V -IRI + Theo n = 25. IRI was induced for 40 min followed by reperfusion. Rats were sacrificed 1, 2, 4, 6, and 24 h after reperfusion. This was preceded by blood and urine sampling for biochemical study of serum Cystatin C (Cys C), serum creatinine, and urinary Cys C. Kidneys were processed for histopathological evaluation and immune-histochemical staining for Cys C. The expression of Cys C in the proximal tubular cells was significantly lower in the IRI group compared to that of the sham group. There was a significant rise in the levels of serum and urinary Cys C after 1 h in the IRI group, while the rise in creatinine occurred later. Dex was superior to NAC and Theo 24 h after the IR insult, and the serum levels of creatinine and Cys C were significantly lower in this group than the other two drug groups (P <0.001 in both cases). Our study revealed a clear benefit for the use of Dex to ameliorate IRI over NAC and Theo if used immediately following the insult. The effect is evident 24-h after its use. The role of serum Cys C as an early marker of acute kidney injury compared to serum creatinine is confirmed.