The protective effect and mechanism of constant mild hypothermia on swine kidney after cardiac arrest and extracorporeal ardiopulmonary resuscitation / 医学研究生学报

ABSTRACT

Objective To evaluate the protective effect and mechanism of mild hypothermia on swine kidney after cardiopulmonary resuscitation, and whether changes in body temperature during mild hypothermia weaken the protective effect of mild hypothermia. Methods 18 swines were randomly divided into constant mild hypothermia group (CMH), variable mild hypothermia group (VMH) and control group (CON), with 6 swines in each group. Cardiac arrest model was successfully made. Then ECPR and temperature management was adopted. The target body temperature was 34℃ in the CMH group, and 37℃ in the control group, while the target body temperature of the VMH group fluctuated from 33 to 35 ℃ every two hours. After 24h, the animals were slowly reheated and then sacrificed. The kidneys were taken for real-time quantitative PCR, immunohistochemistry and histopathological examination. Results The expression levels of Bax, GRP78 and CHOP in the CMH group were lower than those in the CON group. Moreover, the expression of GRP78 in the CMH group were lower than those in the VMH group. The expression of Bcl-2 in the CMH group were higher than those in the VMH group and the CON group, and the expression of Bcl-2 in the VMH group were higher than those in the CON group (all P < 0.05). The positive expression of Bax was the most significant in the CON group and the least in the CMH group. The positive expression of Bcl-2 was the most significant in the CMH group and the least in the CON group. The nuclear membrane of porcine kidney cells shrank, nucleoli shrank and mitochondria swelled obviously in the CON group. The morphological injury changes were mild in the CMH group compared with the VMH group, while the CON group showed the severest change. Conclusion Mild hypothermia could attenuate the renal tubular cells apoptosis after cardiopulmonary resuscitation by inhibiting endoplasmic reticulum stress pathway, thus playing a protective role to the kidney. While aAbnormal temperature fluctuation during mild hypothermia maintenance may weaken the protection of kidney by mild hypothermia.