The effect of electrical stimulation on the cellular localization of HDAC4 protein in early denervated muscular atrophy and its related mechanisms
PAN Lulu1, LIN Sujin1, JIANG Xujian2, CHEN Wenyu2,ZHANG Guowei2, ZHI Yinghao1.
1.Department of Rehabilitation 3, Wenzhou TCM Hospital of Zhejiang Chinese Medical University, Wenzhou 325000, China; 2.Department of Rehabilitation Therapy, Wenzhou TCM Hospital of Zhejiang Chinese Medical University, Wenzhou 325000, China
PAN Lulu,LIN Sujin,JIANG Xujian, et al. The effect of electrical stimulation on the cellular localization of HDAC4 protein in early denervated muscular atrophy and its related mechanisms[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2023, 53(9): 714-720,728.
Abstract：Objective: To explore the effect of electrical stimulation on the cellular localization of HDAC4 protein in early denervation atrophy and its possible mechanism. Methods: SD rats were randomly divided into four groups: normal control group (NC group), simple atrophy model group (MA group), atrophy+ low-frequency electrical stimulation group (20 Hz, LE group), and atrophy+high-frequency electrical stimulation group (100 Hz, HE group), with n=6 in each group. After 8 days of experimentation, the gastrocnemius muscle tissue of the right hind limb was collected for measurement. The average cross-sectional area (CSA) of muscle fibers was detected by immunofluorescence staining, the ultrastructure of muscle fibers and mitochondria was observed by transmission electron microscopy, cAMP concentration was detected by ELISA, Ca2+ concentration was detected by colorimetry, and the total protein expression of CaMKII, PKA, HDAC4 and the expression of nuclear and cytoplasmic proteins were detected by Western blot. Results: Compared with the NC group, the relative weight and CSA of gastrocnemius muscle in the MA group decreased (P<0.05), and the electron microscopy showed disordered arrangement of muscle fibers and degeneration of mitochondria. The total protein and nuclear
protein expression of HDAC4 in the MA group were higher than those in the NC group (P<0.05), while the cytoplasmic protein expression of HDAC4 showed no significant difference. The expression of Ca2+ concentration and CaMKII was decreased (P<0.05), while the expression of cAMP and PKA was increased (P<0.05). Compared with the MA group, the relative weight, CSA, Ca2+ concentration, cytoplasmic protein expression of HDAC4,and CaMKII protein expression in the HE group were increased (P<0.05), so were the nuclear protein expression of HDAC4 and the expression of cAMP and PKA (P<0.05), while the total protein expression of HDAC4 showed no significant difference. Compared with the MA group, the only significantly increased indicators in the LE group were Ca2+ concentration and CaMKII expression (P<0.05), and the other indicators showed no significant difference. Conclusion: Muscle atrophy can occur early after denervation, and the nuclear accumulation of HDAC4 may be an important factor affecting muscle atrophy. High-frequency electrical stimulation (100 Hz) may reduce the nuclear accumulation of HDAC4 by increasing the expression of molecules related to the Ca2+/CaMKII axis and decreasing the expression of molecules related to the cAMP/PKA axis, thereby reversing muscle atrophy.
