The TLR9 Antagonist iCpG-ODN at Different Dosages Inhibits Cerebral Ischemia/Reperfusion Injury in Mice.
BACKGROUND
Inflammatory responses are important mechanisms that are involved in cerebral ischemia/reperfusion(I/R) injury. Whether toll-like receptor 9(TLR9), which belongs to the innate immune system, takes part in the inflammatory responses following cerebral I/R remains unclear.


METHODS
This study examined the effect of different dosages of the TLR9 antagonist inhibitory oligodeoxynucleotide (iCpG-ODN) on cerebral I/R injury by using a mouse model of transient middle cerebral artery occlusion. Neurological function, infarct size, splenocytes and the expression of TLR9 and the downstream products of the TLR9 pathways were determined after cerebral I/R for up to 72 hours.


RESULTS
The Clark's focal symptom scoring showed iCpG-ODN improved neurological deficits following focal cerebral I/R. The iCpG-ODN administration significantly decreased the infarct size in a dose-dependent manner. RT-PCR showed that iCpG-ODN attenuated the I/R-induced RNA expression of TLR9. Immunoblot showed that iCpG-ODN prevented I/R-induced increases in NFκB and IRF7 levels and that it further downregulated the levels of IL-1β, TNF-α, and INF-β in the brain. iCpG-ODN did not alter the levels of TNF-α or INF-β in the peripheral blood or affect stroke-induced changes in the number of splenocytes.


CONCLUSIONS
These findings suggest that iCpG-ODN induced protection against cerebral I/R via inhibiting inflammatory responses in a dose-dependent manner and may be useful in therapy for stroke patients.
Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
Ying
Y
Zhou
Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
Jingrui
J
Pan
Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
Qingxia
Q
Peng
Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
Zhaofei
Z
Dong
Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
Lingna
L
Deng
Department of Neurology, Sun Yat-Sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China.
Yidong
Y
Wang
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D002545:Brain Ischemia / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D050839:Interferon Regulatory Factor-7 / Q000378:metabolism; D016898:Interferon-alpha / Q000378:metabolism; D016899:Interferon-beta / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D009838:Oligodeoxyribonucleotides / Q000008:administration & dosage*; D011897:Random Allocation; D015427:Reperfusion Injury / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D013154:Spleen / Q000187:drug effects / Q000473:pathology; D051217:Toll-Like Receptor 9 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
C587672:IL1B protein, mouse; D050839:Interferon Regulatory Factor-7; D016898:Interferon-alpha; D053583:Interleukin-1beta; C494235:Irf7 protein, mouse; D016328:NF-kappa B; D018696:Neuroprotective Agents; D009838:Oligodeoxyribonucleotides; C495370:Tlr9 protein, mouse; D051217:Toll-Like Receptor 9; D014409:Tumor Necrosis Factor-alpha; C000626952:iCpG-ODN; D016899:Interferon-beta
Brain injury; cerebral ischemia/reperfusion; inflammatory responses; inhibitory oligodeoxynucleotide; pathology; toll-like receptor
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