间歇性酒精暴露对青少年期小鼠酒精犒赏及焦虑行为的影响

The effect of adolescent intermittent ethanol exposure on ethanol-induced conditioned place preference and anxiety-like behavior in adolescent mice

目的探讨间歇性酒精暴露(adolescent intermittent ethanol exposure,AIE)对青少年期小鼠酒精条件性位置偏爱(conditioned place preference,CPP)及焦虑行为的影响。方法 4周龄C57BL/6小鼠随机分为2组,每组10只,AIE组接受间歇性酒精腹腔注射(3 g/kg,25%酒精,共8次),NS组接受生理盐水腹腔注射;随后2组行酒精CPP实验(2 g/kg,20%酒精)。另取一批小鼠经高架十字迷宫(elevated plus maze,EPM)测试后,根据开放臂时间比分为高、低焦虑组,各组中再分别随机分为AIE组、NS组,每组8~10只,分别接受间歇性酒精或生理盐水腹腔注射。之后,4组小鼠再次行EPM测试。结果第1项实验中,与NS组相比,AIE组小鼠的CPP值较高[(116.1±12.9)s vs.(70.8±14.8)s,P=0.035]。第2项实验,高、低焦虑小鼠经AIE处理后,分别与高、低焦虑NS组相比,开放臂时间比差异无统计学意义(均P>0.05)。结论 AIE促进青少年期小鼠酒精CPP的形成,但不改变其焦虑水平,AIE对小鼠酒精CPP的促进作用与焦虑无关。

Objective To examine the effect of adolescent intermittent ethanol exposure (AIE) on ethanol-induced conditioned place preference (CPP) and anxiety-like behavior in adolescent mice.Methods In experiment 1,adolescent male C57BL/6 mice at 4 weeks of age were randomly divided into AIE group and NS group (n=10 for each group).The binge drinking model was established by AIE (3 g/kg,25%).The alcohol reward was evaluated using the ethanol-induced CPP paradigm (2 g/kg,20%).In experiment 2,the anxiety-like behavior of adolescent male C57BL/6 mice were assessed using the elevated plus maze (EPM) test,and the animals were then allocated into high-anxiety mouse (HAM) and low-anxiety mouse (LAM) groups based on the percentage of open arm time (OT%).HAM and LAM were randomly divided into AIE group and NS group (n=8~10 for each group) with random number method,respectively.Then,anxiety-like behavior in four groups was measured again using the EPM test.Results In experiment 1.Ethanol preference (116.1±12.9)s vs.(70.8±14.8)s,P=0.035) was significantly higher in AIE group relative to NS group.However,In experiment 2.The alteration in anxiety-like behaviors was not significant in either HAM-AIE or LAM-AIE groups (all P>0.05).Conclusions AIE reinforces ethanol-induced CPP but does not affect the anxiety-like behavior in adolescent mice,suggesting that AIE may not play a role in anxiety-like behavior.