Role Of TRPA1 In Hyperoxia-induced Lung Injury In Diabetic Mice

Aim:With the increasing incidence and prevalence of diabetes in various countries,the proportion of diabetics in operating rooms and intensive care units is also rising.oxygen therapy is indispensable to diabetics in clinical work,or even need longterm mechanical ventilation.During oxygen therapy,Excessive oxygen concentration can aggravate lung injury,however,the mechanism for diabetic patients are more susceptible to lung injury from hyperoxia exposure is still unclear.Studies have shown that transient receptor potential ankyrin 1(TRPA1)is a non-selective calcium channel,which mediates various sensory processes such as inflammation and pain.Trpal is also involved in the O2 sensing mechanism and is highly expressed in diabetic mice.Therefore,we explored whether the TRPA1 receptor is involved in the pulmonary injury caused by diabetes hyperoxia.Methods:A total of 50 healthy male mice were divided into eight groups by random number table method in order to explore the model of lung injury caused by high oxygen exposure in diabetic mice and the role of TRPA1 in it:Group Ⅰ:control group was exposed to air;Group Ⅱ:diabetes group was exposed to air;Group Ⅲ:control group was exposed to hyperoxia;Group Ⅳ:diabetes group was exposed to hyperoxia;Group Ⅴ:air+TRPA1WT diabetes group;Group Ⅵ:air+TRPA1 KO diabetes group.Ⅶ:hyperoxia+TRPA1WT diabetic group;Ⅷ Group:Hyperoxia+TRPA1 KO diabetes group.Eight groups of mice were intubated after anesthesia,and mechanical ventilated for 2 hours.oxygen concentration>90%was considered as hyperoxia,ventilation pressure was controlled at 15cmH2O,and body temperature of the mice was kept between 34 and 37℃.Alveolar lavage fluid and serum were collected immediately after ventilation to detect the changes of inflammatory factors by ELISA.Middle lobe of right lung was stained with HE and masson,and pathological score was performed under light microscope.Results:(1)After 2 hours mechanical ventilation in groups Ⅰ to Ⅳ,the lung injury score in group Ⅳ was the highest.The average alveolar diameter,alveolar wall thickness,neutrophil number and collagen fiber deposition in diabetic mice were more severely damaged than those in the control group under both hyperoxia and air conditions(P<0.05).When diabetic mice exposed to hyperoxia,the damage of average alveolar diameter,alveolar wall and bronchial wall thickness were further aggravated(P<0.05),and the number of central granulocytes also tended to increase(P=0.15).Inflammatory factors such as IL-2,IL-5,IL-22,IL-33,IL-23,IL-27 and IFN-y in bronchoalveolar lavage fluid of diabetic mice under hyperoxia were significantly increased(P<0.05).(2)After 2 hours of mechanical ventilation in groups Ⅴ to Ⅷ,TRPA1 knockout diabetic mice showed significant improvement in lung injury under either hyperoxia or air,mainly manifested as the thinning of alveolar wall thickness and bronchial wall thickness,the reduction of the number of central granulocytes and the deposition of collagen fibers.Conclusion:Diabetic mice exposed to transient hyperoxia are more likely to develop lung injury,which was mainly shown as increased alveolar wall and bronchial wall thickness,central granulocyte infiltration,extended alveolar diameter,and improved inflammatory factors(IL-2,IL-5,IL-22,IL-33,IL-23,IL-27,IFN-y).Hyperoxia-induced lung injury in diabetic mice can be alleviated by knocking out TRPA1 receptor.These results suggest that the more severe lung injury of diabetic mice under the condition of hyperoxia may be mediated by TRPA1 receptor.