Effects of prophylactic vitamin D application on neuronal activation and behavioral hyperactivity in mice exposed to sevoflurane on postnatal day 10

Objective: This study investigated the effects of prophylactic Vitamin D (Vit D) on behavioral hyperactivity, neuronal activation, neuroinflammation, and neuroapoptosis in mice exposed to sevoflurane on postnatal day 10. Method: Twenty-eight Swiss albino mice were randomly divided into four groups: Vitamin D group (Group D), control group (Group K), sevoflurane group (Group S), and Vitamin D+sevoflurane group (Group SD). Mice in Groups D and SD received daily intraperitoneal injections of 5 µg/kg calcitriol from postnatal day 2 to 10, while mice in Groups K and S received saline injections. On postnatal day 10, mice in Groups S and SD were placed in an anesthesia chamber (35x15x15 cm) for 5 minutes to acclimate to the environment, and their behaviors were recorded. Mice in Groups S and SD were exposed to 2% sevoflurane in 98% O2 for 10 minutes with a flow rate of 2 L/min. Mice in Groups K and D received 100% O2. After exposure, all mice were allowed to recover in a chamber for 40 minutes. Behavioral activities of each mouse were recorded using a camera. Brain sections of the hippocampus and prefrontal cortex from six mice in each group were examined using immunohistochemistry (IH) and electron microscopy (EM). IH was used to evaluate the expression of Interleukin-6 (IL-6), Brain-Derived Neurotrophic Factor (BDNF), Tumor Necrosis Factor-α (TNF-α), c-Fos, B-Cell Lymphoma 2 (Bcl-2), Bcl-2 Associated X Protein (Bax), and Oligodendrocyte Transcription Factor 2 (Olig2). Results: IH analysis revealed that in Group S, the expression of Bax, IL-6, TNF α, and c-Fos in prefrontal cortex and hippocampus tissues was significantly increased, while the expression of Bcl-2, Olig2, and BDNF was significantly decreased compared to Group SD. EM images supported these findings. Behavioral hyperactivity scoring indicated that Vitamin D reduced behavioral activity scores when comparing Group SD to Group S. Conclusion: Our study demonstrated that prophylactic vit D treatment in mice exposed to sevoflurane on the 10th postnatal day significantly reduced the behavioral activity score during the recovery phase. Additionally, it was immunohistochemically shown that Vit D could prevent neuroapoptosis and neuroinflammation caused by a 10- minute single exposure to sevoflurane in the developing brain. Key words: Sevoflurane, vitamin D, IL-6, BDNF, Bax, TNF- α, c-Fos, Bcl-2, Olig2,EM, Behavioral hyperactivity