Preliminary Study And Application Of Pterostilbene On LPS-induced Acute Lung Injury

Acute lung injury(ALI)is a serious respiratory disease in the process of animal feeding,which seriously threatens the safety of livestock and poultry.More and more studies have shown that the development of ALI is closely related to inflammation and oxidative stress.Therefore,reducing inflammation and oxidative stress is of great significance for improving ALI.Pterostilbene is a kind of pure natural substance with biological activity,which mostly exists in common blueberries,grapes and other plants.It has anti-inflammatory,anti-oxidant,anti-tumor,anti-fungal and other pharmacological activities.At the same time,more and more studies have shown that pterostilbene can significantly improve the damage of various tissues and organs.In this paper,we studied the protective effect of pterostilbene on LPS-induced ALI in mice and its potential mechanism.Then pterostilbene was applied to ALI in chicks to observe the protective effects of pterostilbene on chicks.Firstly,LPS-induced ALI mice model was established and treated with pterostilbene(10,20 and 40 mg/kg)respectively.Secondly,the changes of wet-to-dry ratio(W/D)of lung in mice were detected,and the histopathology of H&E staining was observed.The total cells,neutrophils and macrophages in bronchoalveolar lavage fluid(BALF)were counted,and the total protein concentration was determined.The activity of myeloperoxidase(MPO)in lung was determined.And then,the anti-oxidant stress index such as the activities of superoxide dismutase(SOD)catalase(CAT),glutathione peroxidase(GSH-Px)and the oxidant stress index such as the content of malondialdehyde(MDA)in lung were measured.The mRNA expressions of COX-2,i NOS,TNF-α,IL-6 and IL-1β in lung were determined by qRT-PCR.Finally,The protein levels of p-IκB and p-p65 in NF-κB signal pathway and Nrf2 and HO-1 in Nrf2/HO-1 signal pathway were detected by western blotting.The results showed that the LPS-induced ALI mice model was successfully established.Pterostilbene reduced W/D ratio of lung and improved the degree of lung injury in ALI mice,such as sustained the integrity of the lung tissue structure,alleviated pulmonary interstitial edema and alveolar wall thickening,reduced infiltrated inflammatory cells;reduced the number of total cells,neutrophils,macrophages,and total protein concentration in BALF;reduced the activity of MPO in lung;increased the activities of SOD,CAT and GSH Px,and decreased the content of MDA in lung;decreased the mRNA expression of COX-2,i NOS,TNF-α,IL-6,IL-1β in lung;decreased the protein levels of p-IκB and p-p65 in lung;increased the protein levels of Nrf2 and HO-1 in lung.It is suggested that the underlying mechanism involved in the protective effect of pterostilbene on ALI is mainly through inhibiting NF-κB and activating Nrf2/HO-1 signal pathway,that is,inhibiting inflammatory response and oxidative stress response.The results showed that pterostilbene had protective effects on LPS-induced ALI in mice,and could be used as a candidate medication for the treatment or protection of LPS-induced ALI in chicks.LPS-induced ALI chick model was established,and treated by feeding pterostilbene(50,100 and 200 mg/kg)respectively.The chicks were weighed daily,and their intake,mental and physical signs were observed.The shape,color,congestion and necrosis of lung were observed in eyes;the changes of W/D of lung in chicks were detected,and the histopathology of H&E staining was observed;The activity of MPO in lung was determined.The activities of SOD,CAT and GSH-Px and the content of MDA in lung were measured.The mRNA expressions of COX-2,i NOS,TNF-α,IL-6 and IL-1β in lung were determined by qRT-PCR.The results showed that LPS-induced ALI chick model was successfully established,but the daily intake of food and mental and physical signs did not appear to be abnormal;pterostilbene increased the daily growth rate of body weight of ALI chicks.As the dosage of pterostilbene increased,the shape and color of lung tissue tended to be normal,and the congestion and necrosis were improved.Pterostilbene reduced W/D ratio of lung and improved the degree of lung injury in ALI chicks,such as sustained the integrity of the lung tissue structure,alleviated pulmonary interstitial edema and alveolar wall thickening,reduced infiltrated inflammatory cells.Pterostilbene reduced the activity of MPO in lung;increased the activities of SOD,CAT and GSH Px,and decreased the content of MDA in lung;decreased the mRNA expression of COX-2,i NOS,TNF-α,IL-6,IL-1β in lung.The results showed that pterostilbene could protect LPS-induced ALI in chicks.In conclusion,the study confirmed that pterostilbene has protective effect on LPS-induced ALI in mice,and preliminarily revealed that its mechanism of action is achieved by inhibiting inflammation and oxidative stress response,and the application of pterostilbene in the prevention and treatment of chicken ALI also confirmed a good protective effect.The above results not only provide reference for the effective prevention and treatment of ALI in production practice,but also provide experimental basis for the research and development of functional feed additives for chicks.