Protective Effect of Ulinastatin on Acute Lung Injury in Diabetic Sepsis Rats
Authors: Zou Yufeng , Chen Hu , Li Meng-Yu , Tang Lijuan , Jin Zhe , Chen Kai 
Published: October 2021

Abstract
ObjectiveTo establish a rat model of diabetic sepsis, to observe the protective effect of ulinastatin on acute lung injury in diabetic sepsis rats, and to explore the possible mechanism from the aspects of inflammatory response, oxidative stress, hypoxia-inducible factor-1 α expression and pulmonary microvascular permeability. MethodsA total of 50 SPF adult male SD rats were randomly selected, 38 were fed with high fat diet, and the remaining 12 were fed with ordinary diet. Feed five weeks later, the fatty group according to 30 mg/kg body weight, abdominal single injection of STZ, three days after injection, in a random blood glucose or greater tendency for 16.7 L for type 2 diabetes mellitus rats building success, take 36 ChengMo rats were randomly divided into four groups, each group of 12, namely D group of type 2 diabetes, the DS group of type 2 diabetes mellitus and sepsis, Group U ulinastatin pretreatment group. Twelve ordinary feed group were selected as C group, namely blank control group. After successful modeling of type 2 diabetic rats, DS group and U group were injected with endotoxin (LPS) at 5mg/kg via tail vein to construct diabetic sepsis lung injury rat model. Group U was injected with ulinastatin 100kU/kg caudal vein one hour before LPS. 4h later (4 rats in each group were injected with 2 mL 1% Evans blue solution through tail vein half an hour before execution), blood was collected and lung tissues were removed. HE staining was used to observe the pathological changes of lung tissues. The wet/dry ratio (W/D) of lung tissue was determined. Serum IL-1β, IL-18 and TNF-A were detected by ELISA. The contents of malondialdehyde (MDA) and superoxide dismutase (SOD) in serum were detected according to the kit instruction. Western blot was used to detect the hypoxia-inducible factor-1 α (HIF-1α) protein in renal tissue. The expression of TLR4mRNA in lung tissues was detected by rt-pcr. Evans blue staining was used to detect pulmonary microvascular permeability. ResultsCompared with the control group, the lung interstitium in group D was thickened to a certain extent, with a small amount of inflammatory cell infiltration and a little exudate in some alveolar cavities. Compared with D group, DS group had more serious damage, with obvious pulmonary interstitial hyperemia and edema, a large amount of exudation in alveolar cavity, significantly increased inflammatory cells, necrosis and swelling of alveolar epithelial cells. In group U, there were more inflammatory cells in the interstitium and part of alveolar cavities, epithelial cells were exfoliated occasionally in the lumen, and the interstitium widened and the loss was less than that in group DS. Compared with group C, the wet/dry weight ratio (W/D), serum IL-1β, IL-18 and TNF-A contents, hiF-1 α protein expression, TLR4 mRNA expression and pulmonary microvascular permeability of rats in other groups were significantly increased (P<0.01 or P<0.05). The content of MDA and SOD activity in serum decreased (P<0.01). Compared with group D, the wet/dry weight ratio (W/D), serum IL-1β, IL-18 and TNF-A contents, hiF-1 α protein expression, TLR4 mRNA expression and pulmonary microvascular permeability in DS group and U group were significantly increased (P<0.01 or P<0.05). The content of MDA in serum was increased (P<0.01 or P<0.05), and the activity of SOD in DS group was decreased (P<0.01). ; Compared with DS group, the wet/dry weight ratio (W/D), serum IL-1β, IL-18, TNF-A contents, hiF-1 α protein expression, TLR4 mRNA expression, and pulmonary microvascular permeability of rats in GROUP U were significantly decreased (P < 0.01 or P<0.05). The content of MDA in serum decreased (P<0.01), and the activity of SOD increased (P<0.01). Conclusion﻿Ulinastatin can effectively reduce acute lung injury induced by diabetic sepsis in rats, and its mechanism may be related to inhibiting inflammatory response, reducing oxidative stress, regulating hypoxia response pathway and improving pulmonary microvascular permeability.