Abstract: Objective To observe the effect of sevoflurane(SEV) on the expression of myocardial biological clock gene aromatic hydrocarbon receptor nuclear transport-like protein 1(BMAL1) in diabetic rats and to explore its changes. Methods Sixty healthy male SD rats with a body mass of 200-250 g were divided into oxygen inhalation group (NC) and sevoflurane inhalation group (SEV). The diabetic model was routinely replicated, and the model was divided into oxygen group (DM) and sevoflurane group (DM+SEV) with an inhalation time of 5 h(n=15). Four groups of experimental animals were executed at 0, 12 and 24 h after the anesthesia was stopped and then myocardial tissue was isolated. Western blot was used to determine the expression level of biological clock gene BMAL1 protein and its activation enzyme USP9X; HE staining microspy to observe the pathological changes of myocardial tissue and immuno-fluorescence co-localization to observe the relationship between USP9X and BMAL1. Results At 0 and 12 h after stopping anesthesia, the expression of BMAL1 and USP9X in the DM+SEV group was significantly down-regulated as compared with the DM group, and the expression of BMAL1 and USP9X in the DM+SEV group was significantly down-regulated(P＜0.05) at 24 h after stopping anesthesia (P＞0.05). HE staining microscopy found changes of myocardial tissue structure in the DM+SEV group at 0 and 12 hrs after stopping anesthesia. This change was most significant at 0 h after stopping anesthesia, but the myocardial tissue structure was neatly arranged at 24 h. The results of immuno-fluorescence colocalization showed that USP9X and BMAL1 proteins were mainly distributed in the cytoplasm of cardio-myocardium with and overlapping parts between them. Under the influence of sevoflurane, there was less overlap between the two at 0 and 12 hrs after stopping anesthesia and more overlap between the two at 24 h, which was close to that of the DM group. Conclusions Sevoflurane reversibly changes the expression of myocardial circadian clock gene BMAL1 in diabetic rats and this change still existe for 12 h after stopping anesthesia, then significantly fade away 24 hrs after stopping anesthesia.

Key words: sevoflurane, diabetes, myocardium, aromatic hydrocarbon receptor nuclear transport-like protein 1(BMAL1), ubiquitin specific peptidase 9 X-linked(USP9X)