The protective effects of agmatine in zymosan induced acute lung injury in mice

Abstract

To examine the protective effects of agmatine (AGM) administration on zymosan (ZYM)-induced inflammatory response and acute lung injury (ALI) in mice. 32 adult male C57BL/6 mice were randomly divided into four groups (n=8 each) to receive i. p. administration of:() phosphate buffer saline (PBS, 0. 5 ml); © AGM (200 mg/kg); © ZYM (500 mg/kg)+PBS (0.5 ml),and ® AGM (200 mg/kg)-ZYM (500 mg/kg). Blood samples and peritoneal exudates were collected from the animals 12 hours after drug administration for concentration of tumor necrosis factor-a (TNF-a),interleukin-6 (IL-6) and nitric oxide (NO) by enzyme linked immunosorbent assay (ELISA). Lung tissue samples were also collected at the same time for histological examination, and determination of tissue content of TNF-a, IL-6, myeloperoxidase (MPO) activity and nuclear factor-KB p65 (NF-cB p65) DNA-binding activity. 12 hours after ZYM injection, the treated mice became lethargic, their activity and water consumption were both reduced, AGM greatly improved the general status, activity, and water consumption in treated mice, while attenuated the increase of TNF-a (ng/L: 252. 6+ 32. 1 vs. 421. 7- 76. 7, 295. 7 ± 78. 6vs. 592. 0 ± 84. 3, both P<0. 05) , IL-6 (ng/L: 2 198. 8 281.8 vs. 4 725. 3 615.4, 19 829. 3 ± 3 647. Ovs. 47 751. 3 ± 5 264.8, both P<0. 05) and NO (pmol/L: 33. 2 ± 4. 3 vs. 50. 2 ± 5. 2, 14.0 ± 3. 6 vs. 45.4 ± 5. 2, both P<0. 05) in serum and peritoneal exudates caused by ZYM. AGM also attenuated the increase of TNF-a (ng/L: 245. 7 ± 39. 1 vs. 378. 3 ± 67. 6, P<0. 05), IL-6 (ng/L: 810. 3 ± 175. 6 vs. 1 172. 4 ± 203.3,P <0. 05), MPO activity (ng/mg: 24. 9 4. 4 vs. 37. 3 5.8, P< 0. 05) and NF-iB p65 optical density(absorbance value: 0. 272 + 0. 029 vs. 0. 347 ± 0. 037, P 0.05) in the lung tissue seen in ZYM treated animals. There was no significant difference between normal PBS and AGM treated group in all the indexes examined. Histological examination demonstrated that ZYM treated animals had severe inflammatory reaction in lung tissues (manifested as vasodilatation and neutrophils infiltration) and AGM significantly reduced such injury. AGM can attenuate the ALI and inflammation induced by ZYM in mice.