| Objective To observe the changes of learning and memory, behavior,mRNA and protein of cyclooxygenase-2in hippocampus in depressed ratsafter modidified electroconvulsive therapy (MECT), so as to study themechanism of propofol improving the learnin and memory of depressedrats after MECT.Method A total of70clean male Sprague-Dawley rats （12weeks，weighting210±6.4g） were randomly divided into7groups (n=10):control group (group C), depression group (group D), depression+propoflogroup (group DP), depression+electroconvulsive therapy group (group DE),depression+parecoxib group (goup DPa), propofol combined withelectroconvulsive therapy(modified ECT, MECT)group (group DPE) andparecoxib combined with MECT group(goup PaM). Except group C, thedepression model was set up via and chronic unpredictable mildstress(CUMS) in other six groups. Groups DP and DPE received propofol80mg/kg (intraperitoneal injection, I.P.); Groups DPE received ECT (the parameter settings: square wave, current intensity50mA, pulse width0.7ms, frequency50Hz, the time1s)5minutes after intraperitoneal injectionof propofol; Group DP just received propofol; Group E received ECTtreatment only; Group DPa received the same ECT treatment only; GoupPaM received the same treatment with group DPE after30minutes ofparecoxib (I. P.10mg/kg). All treatments were given once1day for7days.The behavior of depressive symptoms was evaluated by sucrose preferencetest (SPT) and the open field test (OFT) respectively before (T1), after(T2)modeling and after treatment (T3); One day after each of the behavior test,the learnin and memory functions were evaluated with Morris watermaze(escape latency and percentage of swimming time in the target quadrant)for6days. After all these tests, put the rats to death, and the hippocampaltissues were rapidly dissected and saved fot further biochemical tests. Thecontent of COX-2mRNA in hippocampus was detected by Reversetranscription polymerase chain reaction (RT-PCR); The expression ofCOX-2protein was detected by immunohistochemistry (IH).Results (1) SPT: Before modeling, no significant difference wasfound among7groups (P>0.05); After modeling, compared with group C,the sucrose preference percentage(SPP) was decreased in other modelgroups (P<0.05)， no difference was found among model groups (P>0.05);Post-treatment, compared with groups D,DPa and DP, the SPP was increasedin group DE, group PaM and group DPE (P<0.05)， no difference was found among the three groups, so as to groups D,DPa and P (P>0.05).(2) Open field test: no significant difference was found among7groupsbefore modeling (P>0.05); After modeling, the scores of the horizontaldistance and frequency of erection were decreased in all model groupscompared with group C (P<0.05); After treatment, the scores of thehorizontal distance and frequency of erection were increased in groups DE,group PaM and DPE compared with goups D. DPa and DP (P<0.05), nodifference was found among groups DE, group PaM and DPE, so as togroups D DPa and DP (P>0.05).(3) Morris water maze: no significant difference was found among7groups before modeling (P>0.05); After modeling, the scores of the morriswater maze were decreased in all model groups compared with group C(P<0.05); Post-treatment, escape latency of Morris water maze wassignificantly increased in group DE compared with other goups.(P<0.05);swimming time percentage in target quadrant of Morris water maze wassignificantly decreased in group DE compared with group C andD PE （P<0.05); No significant difference was found among groups D, DP,DPa, PaM and DPE (P>0.05).(4) The content of COX-2mRNA: compared with groups D and DP, thecontent of COX-2mRNA was increased in group DE (P<0.05); comparedwith group DE, the content of COX-2mRNA was decreased in groups DPEand PaM, and no difference was found among groups D, DP,DPa, PaM and DPE (P>0.05); Group C had the lowest content of COX-2mRNA in allgroups（P<0.05).(5) The expression of COX-2protein: compared with groups D, DP,DPa, PaM and DPE, the expression of COX-2protein was increased ingroup DE(P<0.05), and no difference was foud among the five groups;Group C had the lowest expression of COX-2protein in all groups (P<0.05).Conclusion (1) Sttress could cause depression and dysfunction inlearning and memory, and both propofol and parecoxib could not improvethe learning and memory in depressed rats, and had no influence on themRAN and protein of COX-2in CA3of depressed rats;(2) ECT treatmentcould impair the learning and memory worsely, and the mRNA and proteinof COX-2were signifcantly increased.(3)After the treatment of MECT, thelearning and memory were both improved, the possible mechanism may bethe indirect inhibition on mRNA and protein of COX-2via the anesthisa ofpropofol.(4) During the treatment of MECT, propofol presented a completeinhibition of COX-2. |
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