Role of the Calpain-TRPC6 signaling pathway in sevoflurane-induced developmental neurotoxicity in rats

FANG Chulong; LEI Dingcai; LI Xinghui

doi:10.3969/j.issn.1002-7386.2025.07.003

Abstract：Objective To investigate the effects of the calpain-classical transient receptor potential channel 6(TRPC6)signaling pathway on sevoflurane(S)-induced developmental neurotoxicity in rats.Methods A total of 70 7-day-old Sprague-Dawley(SD)rats were randomly divided into the control group(Veh group,n=26)and sevoflurane group(S group,n=44).In the S group,3％sevoflurane was continuously inhaled for 6h,and arterial blood gas analyses were performed on 10 rats in each group.At 0,4,12 and 24h of sevoflurane inhalation,12 rats in each time point were sacrificed by cervical dislocation,and the remaining 10 rats were subjected to the behavioral test of the Morris Water Maze(MWM)at the age of 6 weeks.A total of 132 7-day-old rats were randomly divided into the Veh group,S group,sevoflurane+5pmmol/L Hypericum perforatum L.(S+H5)group,sevoflurane+10pmmol/L Hypericum perforatum L.(S+H10)group,sevoflurane+SKF96365(20pmmol/L,S+SKF)group and sevoflurane+20pmmol/L Calpeptin(S+CA)group.Twelve rats from each group were anesthetized with sevoflurane for 12h and then decapitated and executed,and 10 rats from each group were taken at 6 weeks of age for the behavioral experiments of MWM.Terminal deoxynucleotidyl transferase nick end labeling(TUNEL)staining was used to detect apoptosis of neurons in the cortex.Western blot was used to detect the protein expressions of TPRC6,Cleaved-caspase-3 and SBDP145 in brain tissues.Results The arterial blood physiological parameters of rats in Veh and S groups were within the normal ranges,and the differences between the two groups were comparable(P＞0.05).Compared with the Veh group,rats in the S group had a significantly prolonged escape latency at 6 weeks of age after birth,and the number of crossing platforms and the residence time in the target quadrant were significantly reduced(P＜0.05).The number of TUNEL-positive cells in the cerebral cortex and the protein expressions of Cleaved-caspase-3 and SBDP145 in the S group at 0,4,12 and 24h of sevoflurane inhalation were significantly elevated,while the protein expression of TRPC6 significantly decreased(P＜0.05).The intervention effect was most obvious at 12 h of anesthesia recovery.Compared with the S group,the number of TUNEL-positive neurons in the cortical neurons of rats in the S+H5 and S+H10 groups significantly decreased,the protein expressions of Cleaved-caspase-3 and SBDP145 significantly decreased,the escape latency was significantly shortened,and the number of times of crossing the plateau and the time of staying in the target quadrant significantly increased(P＜0.05).The number of TUNEL-positive neurons in the cortical neurons of rats in the S+SKF group significantly increased,and the protein expressions of Cleaved-caspase-3 and SBDP145 significantly increased,the escape latency was significantly prolonged,and the number of times of crossing the plateau and the time of staying in the target quadrant significantly decreased(P＜0.05).S+CA group showed a significant decrease in the number of TUNEL-positive cells in rat cortical neurons,a significant decrease in the expressions of Cleaved-caspase-3 and SBDP145,and a significant shortening of escape latency,and significant increases in the number of crossing platforms and residence time in the target quadrant(P＜0.05).While the comparison of swimming speed between the 6 groups,the difference was not statistically significant(P＞0.05).Conclusion Prolonged multiple exposures to sevoflurane in neonatal rats may promote acute cortical neuronal damage and long-term cognitive-behavioral deficits by increasing Calpain-mediated hydrolysis of TRPC6 protein.