ABSTRACT
ObjectiveTo decipher the mechanism of modified Sanpiantang in the treatment of nitroglycerin-induced migraine in rats. MethodSeventy-two Wistar rats were randomized into the control， model （nitroglycerin， 10 mg·kg-1）， positive control （rizatriptan， 0.89 mg·kg-1）， and high- （12.96 g·kg-1）， medium- （6.48 g·kg-1）， and low-dose （3.24 g·kg-1） modified Sanpiantang groups. The rat model of migraine was established by intraperitoneal injection of 10 mg·kg-1 nitroglycerin. The behavioral test was carried out to measure the mechanical pain thresholds （MPT） of the periorbital region and hindpaw after successful modeling. The serum levels of nitric oxide （NO）， tumor necrosis factor-α （TNF-α）， interferon-γ （IFN-γ）， and interleukin-1β （IL-1β） in rats were determined by enzyme-linked immunosorbent assay （ELISA）. Immunohistochemistry （IHC） was employed to determine the expression of inducible nitric oxide synthase （iNOS） in the trigeminal nucleus caudalis （TNC）. Western blot was employed to determine the protein levels of iNOS and phospho-p38 mitogen-activated protein kinase （p-p38 MAPK） in the TNC. Real-time fluorescence quantitative polymerase chain reaction（Real-time PCR） was performed to measure the mRNA levels of iNOS， p38 MAPK， and IL-1β in the TNC. ResultCompared with the control group， the model group showed decreased MPT （P<0.01）， elevated serum levels of NO， TNF-α， IFN-γ， and IL-1β （P<0.01）， and up-regulated expression levels of p38 MAPK， iNOS， and IL-1β in the TNC （P<0.05， P<0.01）. Compared with the model group， modified Sanpiantang increased the MPT （P<0.05）， and the medium-dose group showed the most significant effect （P<0.01）. In addition， modified Sanpiantang down-regulated the mRNA levels of iNOS， p38 MAPK， and IL-1β and the protein levels of p-p38 MAPK and iNOS in the TNC of migraine rats （P<0.05， P<0.01） and lowered the serum levels of NO， TNF-α， IFN-γ， and IL-1β （P<0.05， P<0.01）. ConclusionModified Sanpiantang may treat migraine by down-regulating the expression of pro-inflammatory factors such as NO， TNF-α， IFN-γ， and IL-1β in the p38 MAPK/iNOS signaling pathway to reduce the neurogenic inflammation.