Abstract
AIM: To investigate the effect of magnesium lithospermate B (MLB) on hypoxia/reoxygenation (H/R)-induced elevation of intracellular calcium concentration ([Ca2+]i) and nitric oxide (NO) release in endothelial cells. METHODS: The cultured human umbilical vein endothelial cells (ECV304) were exposed to hypoxia for 30 min under 95 % N2 and 5 % CO2, then reoxygenation for 30 min under air and 5 % CO2. Cell injury was evaluated by dye exclusion test, superoxide dismutase (SOD) assay, and molondialdehyde (MDA) assay. [Ca2+]i was determined by Fura 2-AM. NO content was examined by a NO assay kit. Endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) mRNA expressions were measured by semi-quantitative RT-PCR. RESULTS: Cell viability was decreased from (93.1±1.2) % in normoxia to (88±3) % in H/R (P<0.01), and SOD activity was also decreased from (0.24±0.07) kNU/L to (0.18±0.03) kNU/L in H/R (P>0.05), but MDA production was increased from (1.12±0.06) mmol/L in normoxia to (3.78±0.03) mmol/L in H/R (P<0.01) in ECV304 cultured under calcium conditions. MLB 2.5, 5, and 10 mg/L increased cell viability and SOD activity, and inhibited MDA formation in ECV304. H/R increased [Ca2+]i (F340/F380 from 1.65±0.16 to 1.89±0.28), NO release [from (7.5±1.3) μmol/L to (16±5) μmol/L], and eNOS mRNA expression, but decreased iNOS mRNA expression in ECV304 (P<0.05). However, it did not affect them under calcium-free conditions. MLB inhibited H/R-induced increases in [Ca2+]i and eNOS mRNA expression, stimulated NO release and iNOS mRNA expression (P<0.05). CONCLUSION: MLB attenuates H/R-induced cell injury and increases NO release in ECV304. This increase of NO production is possibly associated with preventing cell injury induced by H/R in MLB-treated ECV304.
Original language | English (US) |
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Pages (from-to) | 930-936 |
Number of pages | 7 |
Journal | Acta Pharmacologica Sinica |
Volume | 23 |
Issue number | 10 |
State | Published - Oct 1 2002 |
Externally published | Yes |
Keywords
- Anoxia
- Calcium
- Endothelium
- Magnesium lithospermate B
- Nitric oxide
ASJC Scopus subject areas
- Pharmacology
- Pharmacology (medical)