Research Of Penehyclidine Hydrochloride Protects Against Traumatic Hemorrhagic Shock/resuscitation Related Lung Injury In Rats

[Background and purpose]Traumatic hemorrhagic shock(THS)is characterized by a high morbidity and mortality.Currently,the preferred clinical treatment are hemostasis and fluid resuscitation etc.,but acute lung injury(ALI)frequently ensue as the most frequent complication.The mechanism of ALI is complicated,and the apoptosis of alveolar epithelial cells is closely related.The premise of alveolar epithelial cells to work properly is mitochondria functioning well and keeping structural integrity.When the permeability of mitochondrial membrane changes,alveolar epithelial cells undergo apoptosis.Studies have shown that the permeability of mitochondrial membranes is mainly regulated by the mitochondrial permeability transition pore(mPTP).Penehyclidine hydrochloride(PHC)can reduce the incidence of pulmonary complications in patients,as well as inhibit the chain inflammatory cascade induced by endotoxin,exert anti-inflammatory effects,but the molecular mechanism underlying the effect of PHC on lung-protection after traumatic hemorrhagic/resuscitation remains unclear.The purpose of this study was to investigate the protective effect of PHC on lung sufferting from traumatic hemorrhagic/resuscitation,and to explore whether it works through mPTP.[Materials and methods]Adult male SD rats were subjected to hemorrhage(arterial bleeding at 0.3 mL/min per 100g body weight)and midline laparotomy.One hour later,rats randomly received penehyclidine alone(0.2 mg/kg),penehyclidine plus the selective mPTP agonist atroctyloside(5.0 mg/kg),or vehicle(n=10 per group)before fluid resuscitation.A separate group of rats receiving sham surgery were included asadditional control.Rats were sacrificed 2 hours after fluid resuscitation to collect lung tissue to apoptosis of alveolar epithelial cells(Annexin V-FITC/PI)and the opening of mPTP,mitochondrial membrane potential(JC-1),as well as Bax,Bcl-2,Caspase-3 and Cyt-c.Using transmission electron microscopy to observe the uultrastructure of mitochondria.[Result]Traumatic hemorrhagic shock increase apoptosis of alveolar epithelial cells(24.06%±5.02%vs.5.66%±2.27%in the sham control,P<0.05).Such an effect was attenuated by penehyclidine(apoptotic rate:11.75%±3.60%).Co-treatment with atractyloside obliterated the effect of penehyclidine(apoptotic rate:20.13±13.51%).The opening of mPTP in the shock group was significantly increased,the opening of mPTP in the PHC group was significantly reduced compared to the shock group,and the mPTP opening in the atractyloside group was significantly greater than that in the PHC group(P<0.05).Penehyclidine attenuated the reduction of mitochondrial membrane potential in response to hemorrhagic shock.Atractyloside co-treatment abolished the effects of penehyclidine.Decreased expression of Bcl-2 and increased expression of Bax,caspase-3 and cyt-c in response to hemorrhagic shock were attenuated by penehyclidine.Atractyloside treatment abolished the effects of penehyclidine on Bcl-2,Bax,Caspase-3 and Cyt-c.The normal structure of mitochondria in the sham group was clearly visible while the mitochondria in the shock group were swollen and the crest disappeared.The pathological changes in the PHC group were significantly lighter than those in the shock group.The pathological changes in the atracyloside group were similar to the shock group.[Conclusion]The pathophysiological mechanism of traumatic hemorrhagic/resuscitation related ALI is related to mPTP-mediated apoptosis of alveolar epithelial cells.PHC exert protective effect of lung by inhibit the opening of mPTP and reducing the apoptosis of alveolar epithelial cells.