Abstract
Objective: To investigate the effect of treatment with different concentrations of ammonium chloride (NH(4)Cl) on the mRNA and protein expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in Chang liver cells. Methods: Normal Chang liver cells were cultured and treated continuously with different concentrations of NH(4)Cl (1.25, 2.5, and 5 mmol/L). The Chang liver cells cultured normally were used as controls. RNA and protein were extracted at the 5th, 10th, and 15th generations. Quantitative real-time PCR, immunohistochemistry, and Western blot were used to measure the expression of HIF-1α and VEGF. Results: Quantitative real-time PCR showed that compared with the control group, the NH(4)Cl treatment group showed significant increases in the mRNA expression of HIF-1α and VEGF across the 5th, 10th, and 15th generations (F = 90976.659/1300.218/1896.800 and 41825.754/2381.321/2591.954, all P < 0.05). The results of immunohistochemistry showed that compared with the control group, the NH(4)Cl treatment group showed significant increases in the protein expression of HIF-1α and VEGF across the 5th, 10th, and 15th generations (F = 376.709/1615.358/1350.120 and 904.789/5105.186/8644.498, all P < 0.05). As was shown by the results of Western blot, compared with the control group, the NH(4)Cl treatment group showed significant increases in the protein expression of HIF-1α and VEGF across the 5th, 10th, and 15th generations (F = 228.499/6051.974/183.219 and 5549.429/40187.665/120982.183, all P < 0.05). Conclusion: Ammonia can increase the expression of HIF-1α and its downstream gene VEGF in Chang liver cells and cause the phenomenon of pseudohypoxemia.