Influence of rosmarinic acid early intervention on the behavior change and the levels of IL-1β and IL-6 in the hippocampus of PTSD model rats / 中华行为医学与脑科学杂志

ABSTRACT

Objective To investigate the effect of rosmarinic acid on the behavioral changes in enhanced single prolonged stress (ESPS) model rats and the levels of interlukin-1β (IL-1β) and interlukin-6 (IL-6) in the hippocampus.Methods 48 adult male Sprague Dawley rats were randomly divided into six groups (n =8)Control group,Control + RA (L) group,Control + RA (H) group,ESPS group,ESPS + RA (L) group and ESPS + RA (H) group.Behavioral changes of these rats were analyzed by open field test and elevated plus-maze.The levels of IL-1 β and IL-6 were measured by enzyme linked immunosorbent assay (ELISA).Results (1) Open field test showed that the number of central region entering and the fraction of time exploring in center of ESPS group were significantly reduced than that of Control group ((18.13 ± 10.15) times,(26.68 ± 10.06) ％) and ESPS + RA (H) group ((16.88 ± 8.81) times,(25.08 ± 8.52) ％) (P ＜ 0.05).And it showed no significant difference among Control + RA(L) group,Control + RA(H) group and Control group.Meanwhile,there was also no statistic difference between ESPS group and ESPS + RA(L) group.(2) Elevated plus-maze test showed that percentages of open arm entries and fraction of time exploring in open arm in reference to total number of entries into all arms and total time spent on all arms in ESPS group were significantly reduced than that of Control group((37.38 ± 8.24)％,(17.63 ±4.74)％) and ESPS + RA(H) group((33.72 ±9.49)％,(16.99 ±4.28)％) (P ＜ 0.05),but there was no significant difference between that of ESPS group and ESPS + RA(L) group(P＞0.05).It also showed no significant difference among Control + RA (L) group,Control + RA (H) group and Control group.(3) Compared with ESPS group,RA(10mg/kg) reduced the levels of IL-1β and IL-6 in the hippocampus,but RA(5mg/kg) did not have this effect.(4) Correlation analysis results showed the level of IL-1β in the hippocampus was negatively related with the ameliorated PTSD-like behaviors of ESPS exposure rats.Conclusion RA can ameliorate PTSDlike behaviors of ESPS exposure rats,and this effect may be carried out by down-regulating the levels of IL-1β and IL-6 in the hippocampus,especially the IL-1β.