Effects of sodium butyrate on the permeability of vascular endothelial cells after severe burn

Yu Xi; Wang Junjie; Qiu Le; Liu Sheng; Wang Fei; Chen Xulin

doi:10.3969/j.issn.1672-8521.2025.03.002

Abstract：Objective:To investigate the effects of sodium butyrate(SB)on vascular permeability and endothelial glycocalyx in vascular endothelial cells after severe burn,and explore its molecular mechanisms.Methods:The cultured human umbilical vein vascular endothelial cells(HUVECs)were divided into the normal serum group,the burn serum group,the low-concentration(SB)group(burn serum+1 mmol/L SB),and the high-concentration SB group(burn serum+3 mmol/L SB).After 12 hours of co-culture,the normal serum group using the serum of healthy people,the burn serum group using the serum of patients with severe burns,and the different concentration SB groups using the serum of patients with severe burns and different concentrations of SB,the expression of protein zonula occludens-1(ZO-1)was detected by Western blotting.The level of vascular endothelial cadherin(VE-cadherin)and the shedding amount of Syndecan-1(SDC-1)in the cell supernatant were detected by enzyme-linked immunosorbent assay(ELISA).The permeability coefficient(Pa)of monolayer endothelial cells was detected by Transwell assay.The changes of glycocalyx layer of endothelial cells were observed under transmission electron microscopy to explore the optimal concentration of SB and the effects on permeability of vascular endothelial cells and glycocalyx.After HUVECs resuscitation,they were divided into the normal serum group,the burn serum group,the burn serum+SB group(burn serum+3 mmol/L SB),and the burn serum+SB+vascular endothelial growth factor(VEGF)inhibitor group(tanshinone ⅡA,concentration:20 μg/mL).The protein expressions of hypoxia-inducible factor 1α(HIF-1α),VEGF and matrix metalloproteinase-9(MMP-9)in cells were detected by Western blotting.Results:Compared with the normal serum group,the expression of ZO-1 protein in the burn serum group was significantly decreased,and the expression of VE-cadherin protein,as well as the shedding amount of Pa and SDC-1 were significantly increased(P＜0.001).Compared with the burn serum group,the shedding amount of Pa and SDC-1 in the low-concentration SB group were significantly decreased(P＜0.01);the expression of ZO-1 protein in the high-concentration SB group increased significantly(P＜0.05);the level of VE-cadherin protein in the high-concentration SB group decreased significantly(P＜0.01).Compared with the low-concentration SB group,the expression of VE-cadherin protein levels,the shedding amount of Pa and SDC-1 in the high-concentration SB group decreased significantly(P＜0.05).The endothelial glycocalyx of HUVECs in the normal serum group was relatively dense and structurally intact.The structure of the endothelial glycocalyx in the burn serum group was damaged and had been fractured and fell off.Compared to the burn serum group,the glycolycalyx layer was denser and the degree of structural damage was less in different concentration SB groups,among which the high concentration SB group was the most obvious.The protein expression of HIF-1α,VEGF and MMP-9 in the burn serum group were significantly higher than those in the normal serum group(P＜0.01).The expression of HIF-1α,VEGF and MMP-9 in the burn serum+SB group were significantly lower than those in the burn serum group(P＜0.01),but were still higher than those in the normal serum group(P＜0.05).The protein expression of HIF-1α,VEGF and MMP-9 in the burn serum+SB+VEGF inhibitor group were significantly lower than those in the burn serum group and burn serum+SB groups(P＜0.01).Conclusions:Sodium butyrate may alleviate the damage to the glycocalyx of vascular endothelial cells after severe burns by inhibiting the activation of the HIF-1α-VEGF-MMP-9 signal pathway,thereby improving the increase in vascular endothelial cell permeability caused by severe burns.