Behavioral and histopathological consequences of transient ischemic stroke in the Flinders Sensitive Line rat, a genetic animal model of depression

Patients with depression have an increased risk for stroke, higher mortality rates following stroke and worse functional outcomes among survivors. Preclinical studies may help to better understand the underlying mechanisms linking these two diseases, but only a few animal studies have investigated the effects of prestroke depression. The present study investigates whether Flinders Sensitive Line (FSL) rats, a genetic depression model, respond differently to focal ischemic stroke compared to control strains (Flinders Resistant Line [FRL] and Sprague-Dawley [SD]). Male adult FSL, FRL and SD rats received a unilateral injection of either vehicle or Endothelin-1 (ET-1) adjacent to the middle cerebral artery (MCA). Motor function was assessed at 48 h followed by euthanasia and infarct volume measurement using 2,3,5-triphenyltetrazolium chloride (TTC) staining and image analysis. In a separate cohort behavior was assessed using standard tests for motor function, locomotor activity, cognition, anxiety- and depression-like behavior beginning at 10 days post-injection followed by infarct quantification. We found that ET-1-induced MCA occlusion produced significant infarcts in all three strains. Stroke animals had slightly impaired motor function, but there was no clear interaction effects between strain and stroke surgery on behavioral outcomes. We conclude that FSL rats show no increased susceptibility to brain damage or behavioral deficits following ET-1-induced focal ischemic stroke compared to controls.