Abstract:

This study aimed to investigate the protective effects of the Tibetan medicinal compound Feirepuqing Powder on a zebrafish model in a hypoxic environment and its effect on the hypoxia-inducible factor 1α (Hif1α). Through establishing a zebrafish hypoxic injury model, behavioral and overall lactate changes under hypoxic conditions were investigated. Experiments were conducted using AB zebrafish larvae 72 h after fertilization. In the control group, 100% standard dissolved oxygen (8.4 mg/L) was used, while in the hypoxia group, pure nitrogen (N₂) gas replacement was used to obtain 50% dissolved oxygen (4.2 mg/L) culture water, and the embryos were treated with 50% hypoxic water add different concentrations of Feirepuqing Powder for 24 h. The zebrafish behavioral analyzer was used to record the swimming trajectory for 30 min, and the Zeblab software was used to derive the movement distance and time during the 30 min. Following the experiment, all the zebrafish from both the groups were homogenized and the lactic acid and lactate dehydrogenase (LDH) content in their tissue were determined. The changes in the Hif1α expression level of the zebrafish in each group were analyzed via western blot (WB) analysis, and the expression of Hif1α in the caudal fin of each group of fish was compared using immunohistochemistry. The results revealed that compared with the hypoxic control group, 10 to 30 mg/L Feirepuqing Powder group significantly increased the hypoxia-induced exercise distance and exercise time (p<0.05), and relative to the hypoxia-induced lactic acid increase (p<0.001), the lactic acid content of the 30 mg/L Feirepuqing Powder group significantly reduced. When LDH activity was compared with that of the hypoxic group, LDH activity was significantly reduced in the 30 mg/L Feirepuqing Powder group (p<0.05). The WB results revealed that when compared with the hypoxia group, Feirepuqing Powder inhibited the expression of Hif1α (p<0.05). Finally, the immunohistochemical results showed that 10 mg/L of Feirepuqing Powder reduced the expression of Hif1α. The results of this study show that Feirepuqing Powder exhibits a protective effect on induced exercise injuries in an acute zebrafish hypoxic injury model and that its hypoxia-tolerance mechanism is related to the expression of Hif1α.

Key words: Feirepuqing Powder, zebrafish, hypoxia, exercise injuries, hypoxia-inducible factor 1α