Protective effect of Polydexyribonucleotide against lipopolysaccharide-induced acute lung injury in rats

Background: Acute lung injury (ALI) is a disorder characterized by widespread inflammation in the lung. Polydexyribonucleotide (PDRN), compound having a mixture of deoxyribonucleotide polymers, stimulates the A2 receptor and has the anti-inflammatory effect. Aim: We investigated the therapeutic efficiency of PDRN on ALI. Methods: Lipopolysaccharide (LPS) was administrated to rats intratracheally to induced ALI (5mg/kg). Rats were randomly classified into the control group (n = 18), ALI group (n = 18), and ALI+PDRN treated group (n = 18). The rats in the PDRN-treated groups underwent intraperitoneal injection of 0.3 ml distilled water including PDRN of 8mg/kg, only once, 1hr after inducing ALI and were sacrificed at 3 h after PDRN administration. Results: Compared with the control group, ALI group have significant high neutrophil counts (/milliliter)(3340 ±760 vs. 9020 ± 420 ; P=0.001), TNF-a(1.00 ± 0.00 vs. 1.52 ± 0.08; P=0.001 and IL-6 (1.00 ± 0.00 vs. 1.60 ± 0.14; P=0.003) in the lung tissue and significant high TNF-α (30.69 ± 3.07 vs. 3326.31 ± 162.06 pg/mL; P=0.000) and IL-6 (35.37 ± 3.54 vs. 2495.50 ± 121.58 pg/mL; P=0.000), in the bronchoalveolar lavage fluid(BALF). In ALI and ALI +PDRN treated group, treatment with PDRN ameliorated ALI-induced impairments lung tissues with suppressing pro-inflammatory cytokine in the lung tissue (TNF-α: 1.52 ± 0.08 vs. 1.01 ± 0.03, IL-6: 1.60 ± 0.12 vs. 0.55 ± 0.02) and BALF (TNF-α: 3326.31 ± 162.06 pg/mL vs. 2112.16 ± 265.92 pg/mL, IL-6: 2495.50 ± 121.58 pg/mL vs. 1545.23 ± 194.54 pg/mL )(all p <0.05). Conclusion: These data demonstrates that protective effect of PDRN on ALI might relate to the suppression of excessive inflammaory response.