[Impact of Ureaplasma urealyticum infection on the MRPS22 protein expression in rat spermatogenic cells and intervening effect of Zhibai Dihuang Decoction].

ABSTRACT

OBJECTIVE: To investigate the impact of Ureaplasma urealyticum (UU) infection (UUI) on the expression of the mitochondrial ribosomal protein S22 (MRPS22) in rat spermatogenic cells and the intervening effect of Zhibai Dihuang Decoction (ZBDH). METHODS: Forty-five SD male rats were randomly divided into four groups of equal number normal control, UUI model control, ZBDH and azithromycin, and the UUI model was made by bladder injection of the standard UU strain in the latter three groups. After modeling, the rats in the ZBDH and azithromycin groups were treated intragastrically with ZBDH at 1 g/kg/d and azithromycin at 0.105 g/kg/d respectively, while those in the normal and UUI model control groups with normal saline at 1 ml/kg/d. At 21 days after intervention, all the animals were sacrificed and their testes harvested for observation of the apoptosis and mitochondrial ultrastructure of the spermatogenic cells, measurement of the mitochondrial membrane potential (MMP) by flow cytometry, and determination of the mRNA and protein expressions of MRPS22 by RT-PCR and Western blot, respectively. RESULTS: The apoptotic index of the rat sperma-togenic cells was significantly higher in the UUI model control than in the ZBDH and azithromycin groups (ï¼»11.23 ± 1.65ï¼½ % vs ï¼»6.62 ± 0.49ï¼½ % and ï¼»7.82 ± 0.81ï¼½ %, P < 0.01), but lower in the ZBDH than in the azithromycin group (P < 0.05). The mitochondrial ultrastructure of the spermatogenic cells was markedly improved in the ZBDH and azithromycin groups as compared with that in the model control. The MMP level was remarkably lower in the model control than in the normal control (ï¼»8.77 ± 1.73ï¼½ % vs ï¼»22.33 ± 1.66ï¼½ %, P < 0.01), but higher in the ZBDH (ï¼»18.26 ± 1.32ï¼½ %) than in the model control (P < 0.01) and the azithromycin group (ï¼»15.91 ± 1.69ï¼½ %) (P < 0.01). The mRNA and protein expressions of MRPS22 were significantly lower in the model control (8.02 ± 3.21 and 22.65 ± 5.31) than in the normal control (15.43 ± 2.54 and 33.31 ± 7.09), ZBDH (11.26 ± 3.82 and 33.35 ± 3.96), and azithromycin group (8.79 ± 2.03 and 28.11 ± 4.13) (all P < 0.01), but both higher in the ZBDH than in the azithromycin group (P < 0.01). There was a positive correlation between the MRPS22 protein expression and MMP (r = 0.639, P < 0.01). CONCLUSIONS: UU infection induces the apoptosis of rat spermatogenic cells by inhibiting the mRNA and protein expressions of MRPS22 and reducing the mitochondrial membrane potential, while ZBDH can decrease the apoptosis of spermatogenic cells by improving the mRNA and protein expressions of MRPS22 and enhancing the mitochondrial membrane potential.