<p>Anxiety-like behavior in rats was assessed using a model of chronic unpredictable mild stress of varying duration, with prior administration of LPS. Chronic unpredictable mild stress induced biphasic changes in anxiety levels: an initial reduction during the early phase of stress exposure followed by a significant increase at later stages. Pre-treatment with LPS modulated the trajectory of anxiety development under conditions of chronic unpredictable mild stress: it exacerbated anxiety-like behavior during the early phase but attenuated its progression in the later stages. These findings suggest promising insights for the development of novel therapeutic strategies targeting stress-induced behavioral disorders.</p>