The relationship between the change in NF-κB and mitochondrion permeability transition pore (MPTP) and apoptosis in denervated skeletal muscles of rats

Objective To analyze the relationship of nuclear factor of kappaB (NF-κB) p65 to mitochondrion permeability transition pore (MPTP) and apoptosis during denervation atrophy of the gastrocnemius muscle, and delineate their potential roles in skeletal muscle atrophy. Methods Thirty Wistar rats were randomly divided into 5 groups: control group, 2 day denervation group, 7 day denervation group, 14 day denervation group, and 28 day denervation group. The gastrocnemius muscle was denervated by transection of the sciatic nerve. Sham operation was done in the control group. Levels of NF-κB p65 protein and the opening of the mitochondrial permeability transition pore in the gastrocnemius muscle were detected respectively by Westem Bloting and confocal fluorescence microscopy. The apoptotic cells in atrophic muscles were quantitated with Tunel. Muscle wet weight was also measure for comparison. Results At different time points after denervation, the levels of NF-κB p65, the opening of MPTP and apoptosis of gastrocnemius were significantly higher than those in the normal group ( P ＜ 0.05). Furthermore NF-κB p65 had a positive correlation with the opening of MPTP (r= - 0.896, P ＜ 0.01) and with the ratio of apoptosis (r = 0.890,P ＜0.01 ), while the increase of NF-κB p65 and apoptosis was negatively correlated with the ratio of muscle wet weight ( r = - 0. 919,-0.924, P ＜ 0.01 ). Conclusion NF-κ3 plays an important role in denervation skeletal muscle atrophy.This effect is related to the opening of MPTP and apoptosis. Key words: Transcription factor NF-κB; Denervation; Muscular atrophy; Apoptosis