Effects of neonatal repeated intermittent inhalation of sevoflurane on learning-memory and Tau protein, p-Tau protein in juvenile and adult rats / 医学研究生学报

ABSTRACT

Objective Learning and memory function is the form of brain higher nervous activity .Hippocampus is the main parts responsible for learning and memory function .Once damaged , it will seriously affect the quality of life in patients .The purpose of this paper was to observe the effects of neonatal repeated intermittent sevoflurane inhalation on learning-memory function and Tau protein , p-Tau protein in brain hippocampus in juvenile and adult rats . Methods Twenty-four healthy SD rats ( n=24 ) were randomly di-vided into juvenile sevoflurane inhalation group ( n=6) , juvenile con-trol group ( n=6);adult sevoflurane inhalation group ( n=6) , and adult control group ( n=6) .Rats in juvenile sevoflurane inhalation group and adult sevoflurane inhalation group inhaled 2.6%sevoflurane at the postnatal 7th day, 14th day, 21th day ( P7,P14,P21) for 2 hours.Rats in juvenile control group and adult control group inhaled the carrier gas (1L/min Air+1L/min O2) at the same time for 2 hours.During P31~37, Morris water maze test was conducted in juvenile sevoflurane inhalation group and juvenile control group to detect the behavior.During P91~97, Morris water maze test was conducted in adult sevoflurane inhalation group and adult control group to detect the behavior .Then hippocampi were taken out to detect the expression levels of Tau protein and p -Tau protein. Results ( 1) Comparison of escape latency at the same time ① Juvenile period: no statistical difference between sevoflurane inhalation group (52.04±41.90,29.77±14.23, 19.87±5.71,22.74±13.73,21.91±9.07) and control group (47.82±8.06,25.26±12.53,23.79±9.49, 20.00±10.10, 14.03±7.55) had (P>0.05).② Adult period: no statistical difference between sevoflurane inhalation group (42.00± 14.12, 26.87±16.93, 19.80±13.76, 15.06±8.45, 8.66±4.82) and control group (41.97±25.66,22.88±10.04,15.88±5.20,9.26± 3.98,11.33±6.05 (P>0.05).(2) Comparison of spatial probe test results:no statistical difference in the swimming times from original area,swimmingresidencetime,swimmingdistanceandspeedbetweengroups(P>0.05).(3)Tauproteinexpressiondetection ①Juvenile period:In the hippocampal CA1 region, CA3 region, DG region, the expression level of Tau in the sevoflurane inhalation group (0.237±0.015, 0.324±0.024,0.226±0.019) was higher than the control group (0.185±0.024,0.232±0.040, 0.184±0.018) (P>0.01).②Adult peroid:no statistically significant difference between sevoflurane inhalation group and control group (P>0.05). (4)p-Tau(Ser396)proteinexpressiondetection ①Juvenileperiod:nostatisticallysignificantdifferencebetweensevofluraneinhala-tion group and control group ( P>0.05) .②Adult period:The expression level in the hippocampal CA3 region of sevoflurane inhalation group (0.170±0.005) was higher than control group (0.158±0.011) (P0.05). Conclusion Neonatal repeated intermittent sevoflurane inhalation has done no harm to learn-ing and memory function of juvenile and adult rats , however , it can result in the significant increase of hippocampal Tau protein expres-sion level in juvenile rats and the increase of hippocampal p-Tau protein expression level in adult rats .