Protective Effects Of Insulin On Smoke Inhalation Injury In Rats' Model

Objective:After building the rat lung injury model, inject insulin to the body, on different timepoints, test tumor necrosis factor-a(TNF-α), interleukin-6(IL-6) and interleukin-10(IL-10) in the arterial blood, the lungs tissue were examined under the microscope and investigate the protective effects of insulin on smoke inhalation injury.Method:Fifty-four rats were randomly divided into three groups,18 for each group: control group, injured group and insulin group. The insulin group were subcutaneously injected 5U/kg insulin after inhalation injury, the injured group were injected the same volume normal saline. Atl2h,24h and 48h, blood glucose were detected, arterial blood was collected and the level of TNF-α, IL-6 and IL-10 were determined. The lungs tissue were examined under the microscope.Results:1 General conditions after inhalation injury:The rats that had suffered from inhalation injury appeared dysphoric, had tachypnea and tachycardia. When in the fresh air they become normal, the rats in control group appeared to have stable respiration.2 The blood glucose in the three groups:The blood glucose of injured group were obviously higher than the insulin group at 12h (P<0.01). The blood glucose of insulin group were obviously lower than the injured group at each points. (P<0.01).3 The macroscopic observation and pathological section of three groups:The lungs of control group on visual inspection had normal color and no congestion and edema. The injured group was found to have severe diffused and passive lung congestion, The insulin group was less edema and fresher than the injured group.The lungs of rats in control group were found no infiltrating inflammatory granulocytes, diffused alveolar septum thickening and spotty hemorrhage.The lungs in the injured group were found edema, heterophil granulocyte, histoleucocyte in lung stroma at 12h points, the insulin group were found less same cells than the injured group at 12h points. The congestion and ergorge of the lungs at 24h were aggravate and more heterophil granulocyte and histoleucocyte were found compared to 12h in the injured rats, there were less histoleucocyte and less congestion of the insulin group. At 48h, the insulin group also has better conditions compared to the injured group.4 The results of TNF-α,IL-6 and IL-10 in the three groups in different timepoints:1) The compartion of TNF-a in three groups:the content of TNF-a in injured group were obviously higher than the control group (P<0.01), the content of TNF-a in insulin group were lower than the injured group (P<0.05) but higher than control group (P<0.01).2) The compartion of IL-6 in three groups:the content of IL-6 in injured group were obviously higher than the control group (P<0.01), the content of IL-6 in insulin group were obviously lower than the injured group at 24h and 48h timepoints (P< 0.01), there were no difference between injured group and insulin group at 12h points.3) The compartion of IL-10 in three groups :there were no difference between injured and control group of IL-10 (P>0.05), the content of IL-10 in insulin group were obviously higher than the control group at three timepoints (P<0.01).the content of IL-10 in insulin group were higher than the injured group at 24hand 48h points (P<0.05).Conclusion:insulin can have some protective effects on smoke inhalation injured rats by decreasing the inflammatory response.