Hydrogen peroxide induces expression and activation of AMP-activated protein kinase in a dental pulp cell line.

AIM: To investigate the effects of hydrogen peroxide on cell viability and expression and activation of AMP-activated protein kinase (AMPK) in rat dental pulp cell line RPC-C2A. METHODOLOGY: RPC-C2A cells derived from rat dental pulp were maintained in MEM supplemented with 10% FBS at 37 degrees C, in a humidified atmosphere at 5% CO(2). Cells were cultured in the presence or absence of H(2)O(2) for up to 60 min at concentrations of from 0.1 to 3.0 mmol L(-1). Cell viability was analysed by WST-1 reduction assay. Expression of AMPK subunit isoforms was analysed by Western blotting using antibodies to the catalytic alpha1 and regulatory beta1 and gamma1 subunit isoforms. The effect of silencing AMPKalpha1 on cell viability was determined using siRNA. RESULTS: Exposure to H(2)O(2) decreased cell viability in a time- and dose-dependent manner. The catalytic AMPKalpha1 subunit and its activated form, phospho-AMPKalpha, increased with exposure to H(2)O(2) in a time- and dose-dependent manner, whereas the regulatory beta1 and gamma1 subunits showed no change. Downregulation of AMPKalpha1 resulted in a reduction in cell viability in H(2)O(2)-treated cells at a concentration of 0.1 mmol L(-1) for 30 min incubation, indicating an increased sensitivity to H(2)O(2). CONCLUSIONS: Reactive oxygen induced energy fuel gauge enzyme AMPKalpha expression and its activation by phosphorylation in RPC-C2A cells, suggesting that AMPK is essential for protection against H(2)O(2)-induced nonapoptotic cell death. Therefore, AMPK may be a therapeutic modulation target for treatment of the dentine-pulp complex injured by reactive oxygen.

Hypoxia induces expression and activation of AMPK in rat dental pulp cells.

AMP-activated protein kinase (AMPK) is a stress-responsive enzyme involved in cell adaptation to an energy crisis. We hypothesized that hypoxia suppresses oxidative phosphorylation and ATP production, resulting in AMPK activation to protect cells. We investigated the effects of hypoxia on cell proliferation, the expression of AMPK and hypoxia-inducible factor 1alpha (HIF-1alpha), the activation of AMPK, and the relationship between AMPK and HIF-1alpha expression in rat dental pulp RPC-C2A cells. AMPK in the cells was composed of catalytic alpha1, and regulatory beta1 and gamma1 subunit isoforms. Cell proliferation was initially suppressed under hypoxia, but it increased thereafter, together with an increase in the expression of AMPK and HIF-1alpha, and the activation of AMPK. Down-regulation of AMPKalpha1 by siRNA inhibited cell proliferation under both normoxia and hypoxia, revealing that AMPK induction and activation were required for cell proliferation, although HIF-1alpha expression under hypoxia was not affected.

[Prophylactic and chemotherapeutic efficacy of pivmecillinam (PMPC) against infections after TUR-P and prostatectomy].

The prophylactic and chemotherapeutic efficacy of PMPC against infections after TUR-P has been investigated. Bacteriological evaluation: PMPC , 200-300 mg/day for 2-12 weeks, was administered to 49 patients, who had over 10(3)CFU/ml of microorganisms after CET or CEC treatment for 3-7 days. The eradication rate of microorganisms was 40.8% after 2 weeks, 52.2% after 4 weeks, 64.1% after 6 weeks, 65.0% after 8 weeks and 70.6% after 12 weeks. Effectiveness on pyuria : The improvement rate of pyuria against 59 patients who had over 10(5)/hpf of pyuria , was 15.3% after 2 weeks, 16.4% after 4 weeks, 25.4% after 6 weeks, 58.5% after 8 weeks, 72.7% after 10 weeks and 75.0% after 12 weeks. Overall clinical efficacy on PMPC was examined in 26 patients. The results of efficacy were 27.3% after 2 weeks, 48.0% after 4 weeks, 50.0% after 6 weeks, 69.2% after 8 weeks, 75.0% after 10 weeks and 77.0% after 12 weeks. The clinical response was evaluated according to a criterion for clinical evaluation of antimicrobial agent on chronic complicated UTI proposed by UTI committee in Japan. No severe adverse effect including allergic reaction was found. Following administration of PMPC , three patients experienced adverse gastric reactions, and drug administration was discontinued at week 6 or 8. PMPC was effective as a prophylactic chemotherapeutic drug against infections after TUR-P and prostatectomy.