Figure 2.

MWM test result comparison before and after modelling (data expressed as mean ± SEM, p < .05 represents statistical significant). A, Escape latency is the time (s) in which the rat swims from the starting point to the hidden platform point at the test day (without the hidden platform). The rats in assigned groups (CTR, SD, PP and ES) were tested before (day 8) and after (day 23) modelling (sleep deprivation + treatment). Escape latency in SD was increased significantly from 9.2 ± 1.8 (before modelling) to 19.4 ± 2.6 (after modelling), whereas the escape latencies in the PP and ES groups show no difference before and after modelling. Therefore, sleep deprivation injured the rats’ capability of finding the platform; pearl powder and estazolam reverse the injury. B, Distance ratio: ratio of swimming distance (m) in target quadrant (the hidden platform stood in at the training days) versus total swimming distance in water pool within 60 s is used to reflect the animal memory. The distance ratio in the SD group was significantly decreased from 60.0 ± 5.0 (before SD) to 35.5 ± 5.6 (after SD), whereas the distance ratio of rats in other groups was not significantly changed before and after modelling. Therefore, SD rats were injured in memory, but PP and ES were capable to prevent memory injury. C, Number of entries into the quadrant with withdrawn platform within 60 s as measurement of spatial memory. Before modelling, the rats in different group show the similar entry times: that is, 2.2 ± 0.28 (CTL), 2.1 ± 0.20 (SD), 2.2 ± 0.33 (PP) and 2.0 ± 0.33 (ES). After modelling, the travel times in SD were 1.4 ± 0.27, decreased by 31.8% (*P < .01). However, the travel times in other groups were not changed or slightly increased after modelling. This indicates the rats treated with PP or ES ameliorate spatial memory deficit induced by SD