Objective:To investigate the effect of ovariectomy on cognition of aged rats.Methods:Sprague-Dawley rats retired from breeding for two reproductive cycles

17-month-old

and 350-400g weight

were divided into three groups.After being operated for 1d

3d

7d

15d and 30d

the rats were tested by Morris water maze to observe the function of learning and mem- ory.Results:There were no differential result between the rats of the three groups in 30d(P>0.05)

and there was no differen- tial result too between the rats of variectomized group and sham operated group in each stage of the full test(P>0.05).Com- pared with the control group

the rats of ovarietomized group and sham operated group showed more escape latency for 1d

3d

Td(P<0.01

P<0.05)

less percentage of swimming length in platform quadrant for 1d

3d

7d(P<0.05)

and less frequency of passing through origin platform quadrant for 1d

3d

7d

15d(P<0.01

P<0.05).Conclusion:Abdominal operation may damage the function of learning and memory

but they will be recovery after 30 days

Simple ovariectomy don’t aggravate more.