[Upregulation of Bcl-2/adenovirus E1B 19-kDa-interacting protein 3 and translocation to mitochondria in nucleus pulposus cells induced by nutrition deprivation].

OBJECTIVE

To detect the expression of Bcl-2/adenovirus E1B 19-kDa-interacting protein 3 (BNIP3) in cell death induced by nutrition deprivation in nucleus pulposus cells so as to further understand the mechanism of death in nucleus pulposus cells.

METHODS

Two adult Sprague Dawley rats, male or female, weighing 150-200 g, were involved in this experiment. The cells isolated from rat caudal disc were cultured under the condition of L-DMEM culture media, 10%FBS, and 21%O2 (control group) and under the condition of DMEM-free glucose culture media, no serum, and 1% 02 (experimental group). The expressions of BNIP3 gene and protein were detected by real-time fluorescent quantitative PCR, immunofluorescence staining, and Western blot. The cell apoptosis rate and mitochondrial membrane potential were measured by flow cytometry at 24, 48, and 72 hours after culture.

RESULTS

The expression of BNIP3 decreased in the control group; the expressions of BNIP3 showed an increasing tendency with time in the experimental group, and BNIP3 combined with mitochondria. Significant differences were observed in the expressions of BNIP3 gene and protein between 2 groups at the other time (P < 0.05) except that no significant difference was observed in the expression of BNIP3 gene at 24 hours (P > 0.05). The cell apoptosis rate and mitochondrial membrane potential were significantly lower in the experimental group than those in the control group (P < 0.05).

CONCLUSION

Upregulation of BNIP3 and translocation to mitochondria may be involved in nucleus pulposus cell death in nutrition deprivation.