Objective   To explore the neurogenesis and blood supply in the piriform cortex of rat with vascular dementia after hyperbaric oxygen therapy.    Methods   SD male rats (at the age of 2 months) were inflicted by permanent ligation of bilateral carotid arteries (2VO). In 30 d after the surgery

the animals having a percentage less than 60% in

active avoidance response (AAR) in shuttle box testing were identified as suffering from vascular dementia (VD). Twenty VD rats were divided randomly into 2 groups: VD group and hyperbaric oxygen group [HBO group

in a tank of 95% oxygen under a pressure of 2.02×10

5

Pa (2ATA)

120 min/d

for 10 d

]

. Another 10 normal rats served as control. In 10 d after the treatment

all rats undertook shuttle box testing for their ability of learning and memory. Their regional cerebral blood flow (rCBF)

regional cerebral blood volume (rCBV) and mean transit time (MTT) in the piriform cortex were measured by CT perfusion imaging. The expressions of Nestin and doublecortin (DCX) in the piriform cortex were detected by immunohistochemical staining.    Results   There was significant difference in AAR rate of shuttle box testing between HBO group and VD group [(49.5±9.3)% vs (27.5±7.9)%

P0.01

]

; Significant difference was also seen in AAR rate between VD group and NC group [(87.5±7.9)%

P0.01

]

. In VD group

the rCBF was declined

rCBV elevated

and MTT was delayed in comparison with the normal control. While hyperbaric oxygen therapy improved rCBF

decreased rCBV

and shortened MTT compared with VD group. The values of rCBF

rCBV and MTT in HBO group were close to those in normal control. In the piriform cortex

Nestin

+

cells mostly located in the layer Ⅱ and layer Ⅲ

and the intensity of positive cells was HBO group VD group normal control;  DCX

+

cells were arrayed as a belt mostly in the layer Ⅱ between amygdaline fissure (af) to rhinal fissure (rf).    Conclusion   HBO therapy enhances the ability of learning and memory and promotes neurogenesis in the piriform cortex of VD adult rats.