Tianjin Medical Journal ›› 2023, Vol. 51 ›› Issue (10): 1071-1075.doi: 10.11958/20230059

• Experimental Research • Previous Articles     Next Articles

Protective effect and mechanism of inosine on acute lung injury induced by lipopolysaccharide in rats

XU Nongyu1,2(), ZHONG Jiangshan1,2, LI Duo1,3,()   

  1. 1. Department of Respiratory and Critical Care Medicine
    2. Inflammation & Allergic Diseases Research Unit
    3. Hospital Infection Management Department, the Affiliated Hospital of Southwest Medical University, Luzhou 646000, China
  • Received:2023-01-28 Revised:2023-05-04 Published:2023-10-15 Online:2023-10-18
  • Contact: E-mail:sclzliduo@163.com

Abstract:

Objective To investigate the lung protective effect of inosine on acute lung injury (ALI) rats and its associated mechanism. Methods Twenty SD rats were randomly divided into 4 group: the control (NC) group, the model (LPS) group, the inosine low-dose intervention (IN-L) group and the inosine high-dose intervention (IN-H) group. Rats challenged with intratracheal lipopolysaccharide (LPS) were treated after 1, 6, and 12 hours with 100 mg/kg inosine (IN-L group), 200 mg/kg inosine (IN-H group) and normal saline (LPS group). The NC group received equal volume normal saline during the modeling and intervention phases. After 24 hours of the induction of ALI, the arterial blood was used to detect partial pressure of oxygen (PaO2), the lung tissue sample was collected for the wet/dry weight (W/D) value and pathological examination. Serum and bronchoalveolar lavage fluid (BALF) were obtained to measure polyadp ADP-ribose polymerase (PARP)-1, inducible nitric oxides (iNOS), tumor necrosis factor (TNF)-α and interleukin (IL)-1β. Lung tissue homogenate was prepared to determine the toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MYD88) and nuclear factor kappa-B (NF-κB) proteins. Results LPS induced lung tissue injury in rats, resulting in severe hypoxemia, increased levels of PARP-1 and iNOS, promoted the secretion of inflammatory factors TNF-α and IL-1β, and up-regulated expression levels of TLR4, MYD88, NF-κB proteins in lung tissue (P<0.05). Inosine intervention down-regulated expression levels of TLR4, MYD88 and NF-κB in lung tissue, decreased the production of PARP-1, iNOS, TNF-α and IL-1β, alleviated the degree of lung tissue injury and improved hypoxemia (P<0.05). The above changes were more obvious in the IN-H group than those in the IN-L group (all P<0.05). Conclusion Inosine inhibits LPS-induced lung inflammation and reduces inflammatory cytokines, which may be related in part to the inosine down-regulation of TLR4/MYD88/NF-κB signaling pathway, the inhibition of PARP-1 activity and the reduction of NF-κB nuclear translocation.

Key words: acute lung injury, lipopolysaccharide, inosine, poly (ADP-ribose) polymerase-1, NF-kappa B, toll-like receptor 4, myeloid differentiation factor 88, nitric oxide synthase

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