Effect of HET0016 combined with mild hypothermia on expression of m-calpain protein in cerebral neurons of neonatal piglets with hypoxic-ischemic encephalopathy

Abstract

Objective To evaluate the effect of HET0016 combined with mild hypothermia on the expression of m-calpain protein in cerebral neurons of neonatal piglets with hypoxic-ischemic encephalopathy (HIE). Methods Thirty-six healthy neonatal piglets (1-2 days after birth), were randomly divided into 4 groups using a random number table: sham operation group (S group, n=6), hypoxia-ischemia and normothermia group (HI+ NT group, n=6), hypoxia-ischemia and mild hypothermia group (HI+ MH group, n=12), and hypoxia-ischemia and HET0016 combined with mild hypothermia group (HI+ HET+ MH group, n=12). The model of HIE was established by using inhalation of the low concentration of oxygen and asphyxia under anesthesia.In HI+ MH and HI+ HET+ MH groups, the body temperature was cooled down to 34 ℃ by using the ice packs at 3 h after establishment of the HIE model.In group HI+ HET+ MH, HET0016 1 mg/kg was infused intravenously at 3 min after cardiopulmonary resuscitation.At 10 days after independent feeding, the animals were sacrificed, brains were removed, and brain tissue specimens were obtained for determination of the expression of m-calpain protein in the putamen, sensory cortex, hippocampal CA3 region, and ventroposterolateral nucleus of the thalamus using the immunohistochemical staining. Results Compared with group S, the expression of m-calpain protein in different brain regions was significantly up-regulated in the other groups (P<0.05). Compared with group HI+ NT, the expression of m-calpain protein in different brain regions was significantly down-regulated in HI+ MH and HI+ HET+ MH groups (P<0.05). Compared with group HI+ MH, the expression of m-calpain protein in different brain regions was significantly down-regulated in group HI+ HET+ MH (P<0.05). Conclusion The mechanism by which HET0016 combined with mild hypothermia inhibits neuronal apoptosis may be related to down-regulation of the expression of m-calpain protein in cerebral neurons of neonatal piglets with HIE. Key words: Hypothermia, induced; Hypoxia-ischemia, brain; Infant, newborn; Neurons; Calpain; HET0016