OBJECTIVE

2

To observe the effects of endogenous metabolite mesaconate combined with Sodium lactate Ringer’s injection （LR） on prolonging the golden treatment time window and its resuscitation efficacy in rats with hemorrhagic shock under high-altitude conditions.

METHODS

2

Rats were divided into the shock group， LR group， and 5， 20， 50 mg/kg mesaconate+LR groups， with 20 rats in each group， to investigate the effect of additional use of mesaconate on the golden treatment time window. After establishing a model of uncontrolled hemorrhagic shock under high-altitude conditions in all groups by housing in a hypobaric hypoxia chamber combined with splenic artery transection， rats in the shock group received no resuscitation， while rats in the LR group and mesaconate+LR groups underwent low-pressure resuscitation with LR or mesaconate combined with LR. Blood pressure control， fluid infusion volume， blood loss rate and survival status were observed in each group. Rats were further divided into the normal group， shock group and mesaconate （50 mg/kg）+LR group， with 10 or 20 rats in each group， to evaluate the resuscitation effects after extending the golden treatment time window by additionally using mesaconate. Except for the normal group， the other groups underwent the same procedure to establish an uncontrolled hemorrhagic shock model under high-altitude conditions. Rats in the shock group received no resuscitation. In the mesaconate+LR group， after 3 h of low-pressure resuscitation， bleeding control was performed by ligation of the spleen artery， and the infusion volume and blood loss rate were recorded； subsequently， the rats received LR resuscitation with twice the volume of blood loss. Then， blood gas indicators of the mesaconate+LR group were measured at different time points. Survival rates， indicators related to sublingual microcirculatory perfusion， liver and kidney blood flow， indicators related to the function of vital organs， and lung and brain water content were observed in all groups.

RESULTS

2

LR infusion alone could effectively maintain mean arterial pressure （MAP） within 50-60 mmHg for approximately 1 h. The administration of mesaconate combined with LR during hypotensive resuscitation could maintain MAP within 50-60 mmHg for over 3 h， with significantly reduced fluid infusion volume and blood loss rate in 50 mg/kg mesaconate+LR group， compared to the LR group （

P

＜0.05）. In the LR group， rats maintained low pressure for up to 1 hour with a survival rate of 52.94%， and no rats survived beyond 2 h. In the 5， 20 and 50 mg/kg mesaconate+LR groups， rats maintained low pressure for up to 1 h with a survival rate exceeding 80%； in the 20 and 50 mg/kg mesaconate+LR groups， rats maintained low pressure for up to 3 h with a survival rate exceeding 70%. After complete resuscitation with mesaconate combined with LR， the 72 h survival rate of rats was 43.75%， and significant improvements in blood gas parameters were observed compared to the end of the shock phase （

P

＜0.05）. Compared to

the shock group， the mesaconate+LR group showed significant recovery in sublingual microcirculatory indicators， and liver/kidney blood flow after complete resuscitation （

P

＜0.05）， with significant reductions in heart， liver and kidney function-related indicators and lung water content （

P

＜0.05）.

CONCLUSIONS

2

Mesaconate combined with LR significantly extends the golden treatment time window for hemorrhagic shock in rats under high-altitude conditions， improves blood gas parameters， sublingual microcirculatory perfusion， and liver/kidney blood flow， mitigates vital organ impairment and pulmonary edema， and increases the survival rate of shocked rats.