Effects of caffeic acid, rofecoxib, and their combination against quinolinic acid-induced behavioral alterations and disruption in glutathione redox status.
OBJECTIVE
The neuroprotective roles of cyclooxygenase (COX) and lipooxygenase (LOX) inhibitors have been well documented. Quinolinic acid (QA) is a well-known excitotoxic agent that could induce behavioral, morphological and biochemical alterations similar with symptoms of Huntington's disease (HD), by stimulating NMDA receptors. However, the exact roles of COX and LOX inhibitors in HD have not yet been explained. The present study aims to elucidate the effects of caffeic acid (a specific inhibitor for LOX), rofecoxib (a specific inhibitor for COX-2), and their combination in ameliorating QA-induced neurotoxicity in rats.


METHODS
QA was injected into the right striatum of rats to induce neurotoxicity. Caffeic acid and rofecoxib were then orally administered separately. In the combination study, caffeic acid and rofecoxib were administered together. After that, a series of behavioral assessments were conducted to determine the effects of caffeic acid and rofecoxib, respectively, and the co-effect of caffeic acid and rofecoxib, against QA-induced neurotoxicity.


RESULTS
Intrastriatal QA administration (300 nmol) not only induced a significant reduction in body weight and motor incoordination, but also altered the redox status (decreased glutathione and increased oxidized glutathione level) in striatum, as compared to the sham group. Moreover, chronic treatment with caffeic acid (5 mg/kg and 10 mg/kg, respectively, p.o.) or rofecoxib (10 mg/kg, p.o.) could significantly attenuate QA-induced behavioral alterations and restore the redox status in striatum. However, at the dose of 2.5 mg/kg, caffeic acid did not show any significant effects on these parameters in QA-treated rats. Furthermore, the combination of rofecoxib (10 mg/kg) and caffeic acid (5 mg/kg) could significantly protect against QA neurotoxicity.


CONCLUSIONS
The in vivo study indicates that excitotoxic injury to the brain might affect oxidant/antioxidant equilibrium by eliciting changes in glutathione. Moreover, the LOX and the COX pathways may be both involved in quinolinic-induced neurotoxicity, which provides a promising target for HD treatment.
Kalonia
Harikesh
H
Pharmacology Division, University Institute of Pharmaceutical Sciences, University Grants Commission, Centre of Advanced Study, Panjab University, Chandigarh, India.
Kumar
Puneet
P
Kumar
Anil
A
Nehru
Bimla
B
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002109:Caffeic Acids / Q000008:administration & dosage / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D052246:Cyclooxygenase 2 Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000378:metabolism; D006816:Huntington Disease / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D007783:Lactones / Q000008:administration & dosage / Q000494:pharmacology*; D016859:Lipoxygenase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010084:Oxidation-Reduction / Q000187:drug effects; D017378:Quinolinic Acid; D051381:Rats; D017208:Rats, Wistar; D045442:Rotarod Performance Test; D012720:Severity of Illness Index; D013450:Sulfones / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
D002109:Caffeic Acids; D052246:Cyclooxygenase 2 Inhibitors; D007783:Lactones; D016859:Lipoxygenase Inhibitors; D013450:Sulfones; C116926:rofecoxib; D017378:Quinolinic Acid; D005978:Glutathione; C040048:caffeic acid