Effect of penehyelidine hydrochloride on TIPE2-TLR4-MyD88 signaling pathway in a rat model of traumatic acute lung injury

Objective To evaluate the effect of penehyelidine hydrochloride (PHCD) on tumor necrosis factor α-induced protein 8-like-2 (TIPE2)-Toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88) signaling pathway in a rat model of traumatic acute lung injury (ALI). Methods Thirty SPF healthy male Sprague-Dawley rats, aged 8 weeks, weighing 190-210 g, were divided into 3 groups (n=15 each) by a random number table method: sham operation group (group Sham), traumatic ALI group (group ALI) and group PHCD.ALI was induced by blunt chest trauma in ALI and PHCD groups.PHCD 2 mg/kg was intraperitoneally injected immediately after blunt chest trauma in group PHCD.The rats were sacrificed and lung tissues were removed at 8 h after the model was successfully established for examination of the pathological changes and ultrastructure of lung tissues (with a light microscope or an electron microscope) and for determination of the wet to dry weight ratio (W/D ratio) and expression of TLR4 and MyD88 in lung tissues. Results Compared with group Sham, the W/D ratio was significantly increased, TIPE2 expression was down-regulated, and the expression of TLR4 and MyD88 was up-regulated in ALI and PHCD groups (P<0.05). Compared with group ALI, the W/D ratio was significantly decreased, TIPE2 expression was up-regulated, and the expression of TLR4 and MyD88 was down-regulated (P<0.05), and the pathological changes of lung tissues and ultrastructure were significantly attenuated in group PHCD. Conclusion The mechanism by which PHCD reduces traumatic AIL is related to activating TIPE2-TLR4-MyD88 signaling pathway in rats. Key words: Cholinergic antagonists; Acute lung injury; Ubiquitin-specific proteases; Toll-like receptor 4; Myeloid differentiation factor 88