Caffeine and CSC, adenosine A2A antagonists, offer neuroprotection against 6-OHDA-induced neurotoxicity in rat mesencephalic cells.
In this study, the cytoprotective effects of caffeine (CAF) and 8-(3-chlorostyryl)-caffeine (CSC), A(2A) receptor antagonists, were tested against 6-OHDA-induced cytotoxicity, in rat mesencephalic cells. Both drugs significantly increased the number of viable cells, after their exposure to 6-OHDA, as measured by the MTT assay. While nitrite levels in the cells were drastically increased by 6-OHDA, their concentrations were brought toward normality after CAF or CSC, indicating that both drugs block 6-OHDA-induced oxidative stress which leads to free radicals generation. A complete blockade of 6-OHDA-induced lipid peroxidation, considered as a major source of DNA damage, was observed after cells treatment with CAF or CSC. 6-OHDA decreased the number of normal cells while increasing the number of apoptotic cells. In the CAF plus 6-OHDA group, a significant recover in the number of viable cells and a decrease in the number of apoptotic cells were seen, as compared to the group treated with 6-OHDA alone. A similar effect was observed after cells exposure to CSC in the presence of 6-OHDA. Unexpectedly, while a significant lower number of activated microglia was observed after cells exposure to CAF plus 6-OHDA, this was not the case after cells exposure to CSC under the same conditions. While CAF lowered the percentage of reactive astrocytes increased by 6-OHDA, CSC presented no effect. The effects of these drugs were also examined on the releases of myeloperoxidase (MPO), an inflammatory marker, and lactate dehydrogenase (LDH), a marker for cytotoxicity, in human neutrophils, in vitro. CSC and CAF (0.1, 1 and 10 microg/ml) produced inhibitions of the MPO release from PMA-stimulated cells, ranging from 45 to 83%. In addition, CSC and CAF (5, 50 and 100 microg/ml) did not show any cytotoxicity in the range of concentrations used, as determined by the LDH assay. All together, our results showed a strong neuroptrotection afforded by caffeine or CSC, on rat mesencephalic cells exposed to 6-OHDA. Furthermore, CSC and caffeine actions, inhibiting MPO as well as LDH releases, would contribute to their possible benefit in the treatment of neurodegenerative diseases, including DP. These effects are partially due to the ability of these A(2A) antagonists to decrease the cells free radicals production and oxidative stress, that are major components of 6-OHDA-induced cytotoxicity.
Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil.
Hélio Vitoriano
HV
Nobre
Geanne Matos de Andrade
GM
Cunha
Lissiana Magna
LM
de Vasconcelos
Hemerson Iury Ferreira
HI
Magalhães
Raimundo Nogueira
RN
Oliveira Neto
Flávio Damasceno
FD
Maia
Manoel Odorico
MO
de Moraes
L Kalyne A Moreira
LK
Leal
Glauce Socorro de Barros
GS
Viana
D058908:Adenosine A2 Receptor Agonists; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002110:Caffeine / Q000494:pharmacology* / Q000627:therapeutic use; D002478:Cells, Cultured; D004660:Encephalitis / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D005609:Free Radicals / Q000378:metabolism; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects / Q000502:physiology; D017628:Microglia / Q000187:drug effects / Q000378:metabolism; D009410:Nerve Degeneration / Q000188:drug therapy / Q000503:physiopathology / Q000517:prevention & control; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use; D009573:Nitrites / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D016627:Oxidopamine / Q000494:pharmacology; D020734:Parkinsonian Disorders / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D043705:Receptor, Adenosine A2A / Q000378:metabolism; D013378:Substantia Nigra / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D013565:Sympatholytics / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology* / Q000627:therapeutic use
C515416:8-(3-Chlorostyryl)-1,3,7-trimethylxanthine; D058908:Adenosine A2 Receptor Agonists; D005609:Free Radicals; D018836:Inflammation Mediators; D018696:Neuroprotective Agents; D009573:Nitrites; D010726:Phosphodiesterase Inhibitors; D043705:Receptor, Adenosine A2A; D013565:Sympatholytics; D014970:Xanthines; D002110:Caffeine; D016627:Oxidopamine