Date Published: August 19, 2019
Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Author(s): Hongzhong Jin, Xiaojia Yang, Kailiang Zhao, Liang Zhao, Chen Chen, Jia Yu.
The research is intended for clarification of the efficacy as well as the underlying mechanism of GSK-3β inhibitors on the advancement of acute lung injuries in acute necrotizing pancreatitis (ANP) in rats.
Seventy-two rats were randomly divided into 6 groups: (1)ANP-vehicle; (2)ANP-TDZD-8;(3)ANP-SB216763;(4)Sham-vehicle;(5)Sham-TDZD-8;(6)Sham-SB216763; Blood biochemical test, histopathological examination and immunohistochemical analysis of rats pancreas and lung tissues were performed. The protein expression of GSK-3β, phospho-GSK-3β (Ser9), iNOS, ICAM-1, TNF-α, and IL-10 were detected in lung tissues by Western-blot.
The outcomes revealed that the intervention of GSK-3β inhibitors alleviated the pathological damage of pancreas and lung (P<0.01), reduced serum amylase, lipase, hydrothorax and lung Wet-to-Dry Ratio, attenuated serum concentrations of IL-1β and IL-6 (P<0.01), inhibited the activation of NF-κB, and abated expression of iNOS, ICAM-1 and TNF-α protein, but up-regulated IL-10 expression in lung of ANP rats (P<0.01). The inflammatory response and various indicators in ANP-TDZD-8 groups were lower than those in ANP-SB216763 groups. Inhibition of GSK-3β weakens acute lung injury related to ANP via the inhibitory function of NF-κB signaling pathway. Different kinds of GSK-3β inhibitors have different effects to ANP acute lung injury.
ANP is an acute abdomen-characterized disease, and it is featured with the advancement of systemic inﬂammatory response syndrome and multiple organ failure syndrome1. Acute pancreatitis associated-lung injury (APALI) refers to commonly-seen and known serious complications of ANP2. Upon it happening, APALI could cause speedy advancement of the disease and increase mortality in ANP patients3. However, the precise mechanism of APALI occurring in ANP patients is still not completely understood; increasing findings show the pathological sequelae of ANP and ANP-related organ failures under the mediation of pro-inﬂammatory cytokines as well as adhesion molecules, comprising TNF-α4, interleukin-1β (IL-1β), interleukin-6 (IL-6) and adhesion molecules (such as ICAM-1) may cause systemic inflammation. At the same time, anti-inflammatory factor (such as IL-10) is restrained and is one of the important factors5,6. Hence, decreasing the harmful pro-inﬂammatory mediators to inhibit the inflammation effectiveness could be an effective treatments for APALI.
All procedures used in the animal experiments conformed to the international guidelines for the care and use of laboratory animals, and were approved by the Laboratory Animal Welfare & Ethics Committee (IACUC) of Wuhan University (WDRM. NO.20171019).
The current research made a preliminary exploration on the effect of different GSK-3β inhibitors on ANP-related lung injuries and its latent mechanism. These outcomes demonstrated a great protection effect of GSK-3β inhibitors against acute lung injuries in ANP. In addition, two different GSK-3β inhibitors are capable of reducing serum amylase and lipase concentrations, pro-inflammatory mediators, pancreatic damage and lung injury. It can also be demonstrated that the protective effect of GSK-3β inhibitors on ANP and related lung injury is achieved by inactivating the NF-κB signaling pathway. All the findings present that GSK-3β inhibitors have an underlying anti-inﬂammation effect and improve the degree of ANP and related lung injuries in rats. At the same time, we also found that the effects of different GSK-3β inhibitors are different, and TDZD-8 shows better anti-inflammatory effects than SB216763. Inhibiting GSK-3β is deemed to suppress pro-inflammatory in several inflammatory diseases including lung injury12,14.Could GSK-3β inhibitors protect the lungs from inflammatory damage caused by ANP? We found that GSK-3β inhibitors reduced the expression of NF-κB p65 in lung tissue of ANP rats. A variety of treatment approaches targeted at the NF-κB signaling pathway like antioxidants, anti-inflammatory agents, or pharmacologic inhibition revealed effectiveness in experimental AP models. NF-κB needs to be transferred from the cytoplasm to the nucleus to activate the NF-κB pathway, which binds to the promoter regions of various pro-inflammatory genes and activates transcription18. Cumulative evidence shows that NF-κB p65, especially the COOH-terminus of p65 at Ser 536, can be phosphorylated by GSK-3β, to strengthen transcriptional responses of NF-κB19. The peculiarity of GSK-3β rests with its capability of affecting the activity of the transcription factor NF-κB20. Some studies found that GSK-3β knockout rats showed an identical phenotype to that of rats that underwent the deletion of the gene for NF-κB p6521. Hence, pharmacologic inhibition of GSK-3β is likely to cause inhibition of the NF-κB transcriptional activity. Our immunohistochemical analysis revealed NF-κB is activated in lung tissue and transferred from cytoplasm to nucleus and a signiﬁcant inhibition of NF-κB p65 by GSK-3β inhibitors in the lung tissues of rats, which conﬁrms GSK-3β inhibitors could suppress activation of NF-κB signaling pathway in lung after ANP.
This study demonstrates the mechanism by which GSK-3β inhibitors alleviate lung injuries depends in part on attenuating the activation of the NF-κB pathway, resulting in a decreased expression of pro-inflammatory cytokines. At the same time, the expression of anti-inflammatory factor was up-regulated. In addition, TDZD-8 has better protection against lung injury than SB216763 related to TDZD-8 has a dual inhibitory effect of non-ATP competitive small molecule inhibition and ATP competitive inhibition. The observations presented in current research are likely to arise more attention to the progression of GSK-3β inhibitors with greater specificity that can be utilized alone or jointly to prevent and treat ANP as well as related lung injuries.