Expression of Autophagy in Different Stages of Neurogenic Bladder after Spinal Cord Injury in Rats

Study design: Experimental study.Objectives: To investigate the expression of autophagy in different stages of the neurogenic bladder after spinal cord injury (SCI) in rats.Setting: Second Hospital of Shandong University, Jinan, China.Methods: A total of 36 Wistar rats were divided into the SCI and control groups. In total, six animals were killed and sampled from each group at 1, 4 and 14 days after surgery of T10-T11 level. BBB scale, residual urine volume and urinary bladder function score were estimated at each time point. The expression of microtubule-associated protein 1 light chain 3 (LC3) and P62 was detected using western blot analysis, immunofluorescence staining or real-time PCR (RT-PCR).Results: The locomotor functions of the hindlimbs and the bladder function of the SCI group rats were lost after surgery, but gradually recovered from 1 day. Western blot showed that the LC3-II/actin was higher in the SCI than in the control group. Immunofluorescence staining revealed that LC3 and P62 were expressed in bladder smooth muscle cell. RT-PCR showed a remarkably increased LC3 mRNA expression at 1, 4 and 14 days in the SCI than in the control group. The P62 mRNA level of the SCI bladder tissues did not differ from that of the control group at 1 day but decreased at 4 and 14 days after surgery.Conclusions: Autophagy is activated during the recovery of the bladder after SCI and sustained. Autophagy may play an important role in bladder neurogenesis and may represent one of the mechanisms of bladder self-repair.