Acute lung injury induced by acute uremia and renal ischemic-reperfusion injury: The role of toll-like receptors 2 and 4, and oxidative stress

Acute lung injury (ALI) is a common complication of distant organ dysfunction induced by acute kidney injury (AKI). Toll-like receptors (TLRs) have a critical role in progression of AKI. The main goal of this study was to determine whether lung gene expression of TLR2 and TLR4 change by ischemic (renal bilateral ischemic-reperfusion; BIR) and uremic (bilateral nephrectomy; BNX) AKI.

Forty male rats were divided into five groups. Two kidneys were removed in BNX, and renal pedicles were clamped in BIR for 45 min. The kidney and lung tissue, and blood samples were collected and saved after 24 hr in all groups. The bone marrow mesenchymal stem cells were immediately injected (1×106,IV) into the treated groups. The expression of TLR2, TLR4, TNF-α, and VEGF was checked by RT-PCR in the tissue samples. MDA level, SOD, and CAT activity were evaluated in the tissue samples.

Structural disturbance of ALI was detected as alveolar hemorrhage and vascular congestion after BIR and BNX.  Lung TLR2 and TLR4 but not TNF-α and VEGF up-regulated in these groups. Oxidative stress stabilized after the BIR and BNX in the tissue samples. BMSCs reduce the expression of TLR2 and TLR4 and oxidative stress in the treated groups. 

Acutely gathering systemic mediators after renal ischemic or uremic injury induce ALI through overexpression of TLR2 and TLR4 and oxidative stress. Therefore, the Lung protective effect of BMSCs may be related to modulation of TLR2 and TLR4 and oxidative stress in the kidney and lung tissue.