TLR4 and bacterial meningitis: However, in hepatic ischemia/reperfusion study, mechanisms that melatonin effectively protect the liver by attenuating the increased level of MyD88, TLR3, and TLR4 protein expression have been intensively investigated, and it was also been found that the inhibitory effects of melatonin on the MyD88 signaling pathway of TLR system was related with suppression of activation of NF-κ B, mitogen-activation protein kinase s (MAPKs), which contribute to the pathogenesis of bacterial meningitis processes [85,86,87].