[Expressions of interleukin-15 and osteopontin mRNA in early stage of acute rejection of renal allograft in rats].

Objective: To study the expressions of interleukin-15 (IL-15), osteopontin (OPN), granzyme B (GraB) and perforin (PFP) mRNA in early stage of acute rejection (AR) of renal allograft in rats.

Methods: The rat renal transplantation model was established. Male Brown Norway and Lewis rats were used as donors and recipients. Four groups were designated: CsA group (BN-->LEW, n = 10, recipients were treated with CsA i.p.); AB group (BN-->LEW, n = 10, recipients were treated with anti-IL-15 neutralizing antibody i.p.); AR group (BN-->LEW, n = 10, recipients were treated with normal saline i.p.) and control group (LEW-->LEW, n = 6, recipients were treated with normal saline i.p.). The blood samples of recipients were drawn at Days 1, 3, 5 and 7 post-transplantation. The serum expressions of IL-15, OPN, PFP and GraB mRNA of recipients were detected by real-time PCR. Allograft tissues were analyzed by pathological assays.

Results: In comparison with other groups, the expressions of OPN, IL-15, PFP and GraB mRNA in AR group were gradually up-regulated and peaked at Day 5. The expressions of IL-15 mRNA in CsA and AB groups were 9685 +/- 1440 and 4346 +/- 741 respectively at Day 5 post-operation. It was significantly lower than that in AR group (17 022 +/- 2153, P < 0.01). The expression of IL-15 mRNA in AB group was significantly lower than that in CsA group (P < 0.01). The expressions of OPN mRNA in CsA and AB groups (13 226 +/- 1565 vs 19 112 +/- 2908) were both significantly lower than that in AR group (24 663 +/- 2449, P < 0.01). But the expression of OPN mRNA in AB group was higher than that in CsA group (P < 0.01). At Day 5 post-transplantation, both the expressions of PFP and GraB mRNA in AB and CsA groups was lower than that in AR group (P < 0.01). The pathological results showed that severe AR occurred at Day 7 post-transplantation in AR group and whereas the extent of rejection sign relieved in AB group.

Conclusion: In early stage of AR of renal allograft in rats, the expressions of OPN, IL-15, PFP and GraB mRNA are up-regulated. Blocking IL-15/IL-15R pathway in early stage of AR can down-regulate the expressions of PFP and GraB mRNA.