Study On The Molecular Mechanism Of Attenuating Pulmonary Edema In Severly Scalded Rats By Complementing Sodium Hypertonic Fluid In The Early Stage

ObjectiveTo explore the molecular mechanism on attenuating pulmonary edema in severelyscalded rats by supplementing200mmol/L hypertonic salt solution (HS) versuslactated Ringer’s solution (LR) in the early stage.MethodsFifty-six SD rats were randomly divided into three groups: control group, sodiumlactate Ringer’s solution group (group LR) and hypertonic sodium solution group(group HS). Neck vein catheterization was used on all rats and scald resuscitationtherapy was only adopted in the rats between group LR and group HS. The specimensof blood and lung tissue were acquisited in the control group and at2h,8h and24hafter treatment in the group LR and group HS.Part I: Study on the change of blood sodium and inflammatory mediators ofseverly scalded rats by complementing sodium hypertonic fluid in the early stageThe tests were made respectively in the control group and at2h,8h,24h afterfluid resuscitationg in the group LR and group HS, which covers the following aspectssuch as moisture content of lungs, blood sodium, tumor necrosis factor-α (TNF-α),interleukin6(IL-6), lung tissue myeloperoxidase (MPO) and lung tissuemalondialdehyde (MDA). The data drawn from the test were statistically analyzed. Part II: Study on the change of MAPK of severly scalded rats by complementingsodium hypertonic fluid in the early stageThe p38MAPK activity contents of blood mononuclear cells were maderespectively in the control group and at2h,8h,24h after fluid resuscitationg in thegroup LR and group HS with Western blotting. The data were statistically analyzed.The immunohistochemical method was used to determination p38MAPK activationlevel of lung tissue in the control group and at2h,8h,24h after fluid resuscitation inthe group LR and group HS. The pictures were compared.ResultsPart ⅠThe pulmonary water contents of the group HS and group LR at each time pointafter resuscitation were significantly higher than that of the control group, thedifference was statistically significant (P<0.05or P<0.01). The pulmonary watercontents of the group HS was significantly lower than that of the group LR, thedifference was statistically significant (P <0.05or P <0.01). The serum sodium of thegroup HS at each time point after blood recovery was higher than that of the group LR,the difference was statistically significant (P <0.01). The serum sodium of the groupLR at each time point after blood recovery was significantly lower than that of thecontrol group, the difference was statistically significant (P <0.01). The serumsodium of the group HS at each time point after blood recovery compared with thecontrol group, the difference was not statistically significant (P>0.05). TNF-α andIL-6of the group HS and group LR at each time point after the recovery weresignificantly higher than those of the control group, the difference was statisticallysignificant (P <0.05or P <0.01). TNF-α and IL-6of the group HS at each time pointafter the recovery compared with group LR, the difference was not statisticallysignificant (P>0.05). The pulmonary tissue MPO and MDA levels of the group HSand group LR at each time point after resuscitation were significantly higher than those of the control group, the difference was statistically significant (P <0.05or P <0.01).The pulmonary tissue MPO and MDA levels of the group HS at each time point afterresuscitation was significantly lower than that of the group LR, the difference wasstatistically significant (P <0.05or P<0.01). The pulmonary tissue MPO and MDAlevels of the group HS at each time point after resuscitation compared with the controlGroup, the difference was not statistically significant (P>0.05).Part ⅡThe p38MAPK activity contents of blood mononuclear cells was almost noexpression in the control group, and were significantly expressed in the group HS andgroup LR at each time point after resuscitation, the difference was statisticallysignificant (P <0.01). The expression of the p38MAPK activity contents of bloodmononuclear cells in the group HS had no obviously difference with the group LR (P>0.05). The p38MAPK activity contents of lung tissue by immunohistochemical assayin the group HS at2h,8h,24h after fluid resuscitation were significantly expressed incomparison with the group LR, and had no obviously difference with the control group.The p38MAPK activity contents of lung tissue in the group LR at2h,8h,24h afterresuscitation increased significantly expression compared with the control group.Conclusion(1) Using200mmol/L hypertonic sodium solution for fluid resuscitation cansignificantly reduce the pulmonary edema and improve hyponatremia compared withsodium lactate Ringer’s solution in severely scalded rats during early stage.(2) Using200mmol/L hypertonic sodium solution for fluid resuscitation have nosignificant difference on cytokines such as TNF-α and IL-6in comparison with sodiumlactate Ringer’s solution in severely scalded rats during early stage.(3) Using200mmol/L hypertonic sodium solution for fluid resuscitation cansignificantly reduce the MPO and MDA content of lung tissue, and reduce lung neutrophil accumulation and the production of oxygen free radicals, and reduce the lungtissue injury in comparison with sodium lactate Ringer’s solution in severely scaldedrats during early stage.(4) Using200mmol/L hypertonic sodium solution for fluid resuscitation has nosignificant difference on p38MAPK activity contents of blood mononuclear cells incomparison with sodium lactate Ringer’s solution in severely scalded rats during earlystage. Compared with sodium lactate Ringer’s solution, the p38MAPK activity contentsof lung tissue are reduced obviously using200mmol/L hypertonic sodium solution forfluid resuscitation in severely scalded rats during early stage.