Anesthesia/stereotaxic surgery exposure affects cognitive impairment and hippocampal synaptic plasticity dysfunction in male rats

Year 2024, Volume: 41 Issue: 2, 259 - 263, 19.05.2024

Osman Sinen , Ayşegül Gemici Sinen , Narin Derin

Abstract

Postoperative cognitive dysfunction (POCD) is a frequent complication after major surgery and anesthesia exposure, particularly in advanced aging. However, the effects of anesthesia/stereotaxic surgery (A/SS) on cognitive function in rats remain inadequately understood. This study aims to elucidate the effects of A/SS on cognitive function in male Sprague Dawley rats and explore potential alterations in hippocampal synaptic plasticity. Male Sprague Dawley rats, aged 6 months, were subjected to anesthesia (A) or A/SS, involving anesthesia with ketamine/xylazine (50/10 mg/kg, ip) and stereotaxic surgery to create a burr hole above the lateral ventricle. Anxiety-like behavior and locomotor activity were assessed using the open-field test one week post-surgery. Spatial memory and learning were evaluated through the Y-Maze test and novel object recognition test (NORT). Moreover, to determine hippocampal synaptic plasticity, we evaluated hippocampal long-term potentiation (LTP) at perforant pathway-dentate gyrus synapses. No statistically significant differences in anxiety and motor activity were observed between groups. Compared to the no-treatment group, the A/SS group rats exhibited a significantly (p<0.05) lower exploration of a novel arm and novel object in the Y-Maze and NORT, respectively. Furthermore, on postoperative day 7, LTP induced by high-frequency stimulation in the dentate gyrus region was attenuated (p<0.05) in the A/SS group compared to the no-treatment group. These findings indicated that A/SS induced cognitive decline and functional synaptic plasticity dysfunction. The results of the present study may be useful for future studies examining cognitive functions in experimental models involving such procedures.

Keywords

Stereotaxic surgery, Anesthesia, Postoperative cognitive dysfunction

Ethical Statement

All experiments were performed in accordance with the Guide for the Care and Use of Laboratory Animals and approved by the Animal Ethical Committee of Akdeniz University (with unique authorization number B.30.2.AKD.0.05.07.00/43).

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