Tree shrew is a novel and high-quality experimental animal model. In this study, the real-time polymerase chain reaction methods were established to detect infection-related cytokines interleukin-6 (IL-6), IL-8, IL-10, IL-17A, interferon-γ (IFN-γ) and housekeeping gene glyceraldehyde-phosphate dehydrogenase (GAPDH) of tree shrew. The results indicated that the establised methods had good specificity. The high point of the linear range of these reagents reached 1 × 1010 copies, and the low points ranged from 10 copies (IL-6, IL-17A), 100 copies (IL-10, GAPDH) to 1 000 copies (IL-8, IFN-γ). In this interval, the linear correlation coefficient R2 of each reagent was greater than 0.99. The lowest detectable values of IL-6, IL-8, IL-10, IL-17A, IFN-γ and GAPDH were 8, 8, 4, 8, 128 and 4 copies, respectively. The results showed that the established detection methods had good specificity, sensitivity and wide linear range. The methods were suitable for detection of multiple concentration range samples, and could be used for the subsequent studies of tree shrew cytokines.
Objective To explore the clinical application value of electrical impedance tomography (EIT) individualized adjustment of positive end-expiratory pressure (PEEP) in patients with acute respiratory distress syndrome (ARDS). Methods The ARDS patients requiring mechanical ventilation who admitted between April 2019 and March 2022 were recruited in the study. They were randomly divided into 3 groups with 12 cases in each group. Optimal PEEP was set using ARDSnet method (a control group), lung ultrasound scoring method (LUS group) and EIT adjustment method (EIT group). The changes of hemodynamics, blood gas analysis, respiratory mechanics, extravascular lung water index and other indicators of the patients were recorded at each time point. Results There was no significant difference in PEEP between the EIT group and the LUS group, but PEEP in both the EIT group and the LUS group was significantly higher than the control group (P<0.05). After 12 hours of treatment, the dynamic lung compliance of the control group did not change significantly, while the dynamic lung compliance ventilation of the LUS group and the EIT group was significantly improved for 12 hours, and the improvement in the EIT group was significantly better than that in the control group (P<0.05). After treatment, the oxygenation index in the three groups was significantly increased, and the oxygenation index in the EIT group was significantly higher than that in the control group (P<0.05). There was no significant difference in hemodynamics between the three groups before and after treatment (P>0.05). The extravascular lung water index of the three groups after treatment was significantly decreased, and the LUS group and the EIT group decreased more significantly than the control group (P<0.05). Conclusion In the PEEP setting of ARDS patients, the use of EIT personalized adjustment method can effectively improve the patient’s lung compliance and oxygenation index, and reduce extravascular lung water, without affecting hemodynamics.