Changes of vasoactive substances and adrenergic beta receptors in rabbit models of neurogenic pulmonary edema / 中国小儿急救医学

ABSTRACT

Objective To establish an animal model of neurogenic pulmonary edema (NPE),and to study the role of catecholamine and beta receptors in the occurrence of NPE. Methods The NPE model was established by injecting fibrinogen and thrombin into the cerebellum medullary pool of the rabbits. Twenty-four rabbits were divided into the control group,the saline group and the experimental group by random num-ber table. In the control group,only cerebellar medullary cistern puncture was carried out,and no drug was in-jected. Cerebrospinal fluid was drew out and the same amount of saline was injected into the cerebellum me-dullary pool in the saline group. Fibrinogen and thrombin were injected into the cerebellum medullary pool in the experimental group. The animals were intubated by tracheotomy,the femoral artery and the internal jugu-lar vein were dissected and connected with the PiCCO instrument to detect the blood pressure,heart rate,and respiratory rate before puncture and at 1 min,10 min,30 min after puncture. Serum samples were collected for the determination of epinephrine,norepinephrine,acetylcholine,endothelin-1,cardiac troponin I,brain natri-uretic peptide and neuropeptide Y levels before puncture and at 1 min,10 min after puncture. The rabbits weresacrificed at 3 hours after successful modeling,the pathological examination of lung was performed. Myocar-dial samples were taken to detect adrenergic beta receptors mRNA. Results (1)The heart rate,respiratory rate and mean arterial pressure at 1 min and 10 min after puncture in experimental group were significantly higher than those in control group and saline group. (2) The pathological examination of the rabbits′ lungs in experimental group found that the lung tissue was swollen and dark red in appearance with large areas of con-gestion. Under the microscope,the lung tissue was edema,bleeding,and inflammatory cells were infiltrated in the alveolar cavity,which was consistent with characteristics of NPE. (3)There was no difference in epineph-rine and norepinephrine concentration in all groups before the cerebellar medullary pool puncture. The concen-tration of epinephrine and norepinephrine at 1 min after puncture time were (200. 0 ± 251. 7)μg/ L,(448. 9 ± 356. 7)μg/ L in the experimental group,whcih were significantly higher than those of control group[(15. 4 ± 3. 4)μg/ L,(15. 9 ± 9. 7)μg/ L] and saline group[(17. 1 ± 3. 8) μg/ L,(29. 6 ± 18. 4) μg/ L] (P < 0. 05). The concentration of epinephrine and norepinephrine at 10 min after puncture were (397. 0 ± 797. 7)μg/ L, (221. 4 ± 173. 7)μg/ L in the experimental group,whcih were significantly higher than those of control group [(23. 3 ± 6. 4) μg/ L,(18. 8 ± 3. 9) μg/ L] and saline group[(16. 7 ± 9. 1) μg/ L,(20. 3 ± 6. 5) μg/ L] (P < 0. 05). (4)There was no significant difference in the levels of serum neuropeptide Y,acetylcholine and endothelin-1 among the three groups. (5)The mRNA of adrenergic beta-1 receptor in the experimental group was 0. 37 ± 0. 12,which was significantly lower than those in the control group (0. 54 ± 0. 13) and saline group (0. 56 ± 0. 14) (P < 0. 05). There was no significant difference in adrenergic beta-3 receptor mRNA among the three groups. Conclusion The NPE animal model was constructed by injecting fibrinogen and thrombin into the cerebellum medullary pool of the rabbits. Catecholamine and beta-1 receptor play a role in the occurrence of NPE rabbit model. There is no significant correlation between neuropeptide Y,acetylcholine,en-dothelin-1 and the occurrence of NPE in rabbits.