Abstract: Objective To investigate the mechanism of donation related vasovagal reaction (DRVR) by analyzing the plasma levels of endothelin-1 (ET-1) and nitric oxide (NO) in blood donors with DRVR. Methods From January 2021 to May 2022, 83 blood donors with DRVR at China Three Gorges University were enrolled in the DRVR group, and 77 blood donors with no adverse reaction were enrolled in the control group. The plasma ET-1 and NO levels of blood donors were detected by antibody/antigen sandwich ELISA. The data were analyzed by independent sample t test. Results The plasma levels of ET-1 in the DRVR and control groups were 24.3（17.9~34.0）pg/mL,and 20.0（17.9~24.7）pg/m (u=2 400,P<0.05), while the plasma NO contents were 23.8（21.4~28.7）pg/mL, and 25.9（23.3~31.9）pg/mL（u=2 395,P<0.05）. The ET-1/NO values of the two groups were 0.85（0.68~1.1）and 0.79（0.57~0.94）（u=2454,P<0.05）. Conclusion Blood donation stress increases plasma ET-1 level, decreases NO level, and increases ET-1/NO ratio, a phenomenon more evident in blood donors with vasovagal reaction, who have greater psychological pressure resulting from blood donation. The occurrence of donation related vasovagal reaction may be mainly related to the psychological factors regulating blood donors' stress.

Key words: Adverse reactions of blood donation, Donation related vasovagal reaction, Plasma endothelin, Plasma nitric oxide