| Objective: To explore the regulatory effect of calcium-sensing receptor(Ca SR)on the calcineurin/ nuclear factor of activated T cells pathway(Ca N/NFAT pathway)in the rat model of hypoxic-ischemic encephalopathy(HIE),and to research the immune mechanism after brain injury of HIE,so as to provide a new idea for the prevention and reduction of nerve injury of HIE.Methods: One hundred and fifty-seven-day-old healthy SD rats were randomly divided into six groups,sham group,HIE group,NPS2390 group,spermine group,NPS2390+ spermine group,and FK506 group.The degree of neurological damage was observed by Longa score 24 h after operation.Rats were randomly selected from the sham operation group and HIE group,HIE model mice were trained with early exercise intervention until the age of 21 days,suspension test,plane straightening test,inclined board test to observe the motor function of the sham group,HIE group and intervention group;He staining and electron microscopy were used to observe the morphology of neurons in the cerebral cortex and hippocampus of rats in each group.The protein expression of Ca SR,Ca MKⅡ and Ca N/NFAT pathway in brain tissues of rats were observed by immunohistochemistry,western blot and real-time PCR.Results: According to Longa score and morphological results,HIE model was successfully established.Early rehabilitation intervention training can improve the motor dysfunction of HIE model rats.According to the results of HE staining and electron microscopy,the nerve cells in HIE group were obviously damaged compared with those in sham group.Spermine can aggravate nerve damage in HIE rats,NPS2390 and FK506 alleviated neuropathic changes in HIE rats.Immunohistochemical results showed that in hippocampal CA3 region,the expression of Ca SR and Ca N in HIE group was significantly higher than that in sham group(P<0.05),Ca SR and Ca N protein level in spermine group was higher than that in HIE group(P<0.05),and NPS2390 group and FK506 group were lower than that in HIE group(P<0.05).In the cerebral cortex,the expression of Ca SR in HIE group was higher than that in sham group(P<0.05),the expression of spermine group was higher than that in HIE group(P<0.05),and the expression of NPS2390 group and FK506 group were lower than that in HIE group(P<0.05),but there was no significant difference in the expression of Ca N.The results of Western blot showed that the expression of Ca MKⅡ,Ca N and NFAT in HIE group was higher than that in sham operation group,the expression of Ca MKⅡ,Ca N,NFAT in spermine group was higher than that in HIE group,the expression of Ca MKⅡ,Ca N,NFAT in NPS2390 group FK506 was lower than that in HIE group,the expression of Ca MKⅡ,Ca N in NPS2390+ spermine group was lower than that in HIE group,and the expression of NFAT was higher than that in NPS2390+ spermine group.Conclusion: In HIE rats,the expression of Ca SR aggravated the damage of nerve cells;Ca SR can activate the expression of Ca N/NFAT pathway,and inhibiting Ca N/NFAT pathway can play a protective effect on hippocampal neurons of HIE rats;intervention of early rehabilitation intervention can improve HIE motor dysfunction in model rats. |
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