Objective: To explore the relationship of cell apoptosis and expression regularity of hypoxia-inducible transcription factor (HIF)-1 alpha after severe burn with delayed fluid resuscitation in areas of different altitude.
Methods: A total of 240 male Wistar rats, which were raised in areas of different altitude (1,517 and 3,840 meters), were employed as the experimental models [They received a 30% total body surface area (TBSA)III degree scald injury], and then they were randomly divided into 3 groups: delayed fluid resuscitation group (DFR, n=50), immediate fluid resuscitation group (IFR, n=60) and control group (CG, n=10). Renal tissue samples were harvested at 1, 6, 12, 24, 72 and 168 hours after burn, respectively. Cell apoptosis was detected by tissue chip technology and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL). The expression of HIF-1 alpha was assessed by immunohistochemistry and image analysis.
Results: With increase in altitude, cellular edema, degeneration, necrosis and disintegration of renal tissue were gradually worsening, the capillaries of renal glomeruli became dilated and engorged, with degeneration and necrosis of endothelial cells, engorgement and edema of renal interstitium, and infiltration of inflammatory cells. Pathological changes in DFR group were more serious than that of IFR group. Cell apoptosis and the expression of HIF-1 alpha were both enhanced, the latter mainly appeared in nuclei of renal cells, and they were more marked at 3,840 meters compared with those at 1,517 meters. They were more marked in experimental groups than in control group, especially so in DFR group (P<0.01). Cell apoptosis was positively correlated with the expression of HIF-1 alpha (r= -0.651, P<0.01).
Conclusion: Severe burn at high attitude plateau results in high expression of HIF-1 alpha and an increase in apoptosis of renal cells. HIF-1 alpha plays a role in kidney cell apoptosis.