Objective To observe the characteristics of changes in tissue oxygen partial pressure in Zusanli (ST36) acupoint and related organs in acute respiratory distress syndrome (ARDS), and to clarify the correlation between oxygenation of local tissue and systemic oxygenation and the correlation between oxygen metabolism of acupoint tissues and related organ tissues.Methods Twenty healthy New Zealand white rabbits were selected and divided into an ARDS model group and a control group, according to random number table method, 10 in each group. Oleic acid (0.08 - 0.1 mL/kg) intravenous injection was used to replicate the ARDS animal model. Only tracheotomy, mechanical ventilation, insertion of arterial/venous catheter, etc other manipulations were conducted, and no oleic acid was injected in the control group. Tissue oximeter was used to determine the fraction of inspired oxygen (FiO2), when FiO2 was 0.21 and 1.00 respectively, the tissue oxygen partial pressure (PtO2) in Zusanli acupoint, stomach and liver was measured. Meanwhile, the blood gas analyses of arterial blood and mixed venous blood were carried out to calculate the oxygen extraction rate (O2ER).Results When FiO2 was equal to 0.21, the levels of PtO2 in Zusanli acupoint, stomach and liver of the ARDS model group were significantly higher than those of the control group in the same period; the partial pressure of oxygen arterial blood (PaO2), partial pressure of oxygen in mixed venous blood (PvO2), arterial oxygen saturation (SaO2), mixed venous oxygen saturation (SvO2) and O2ER of the ARDS model group were significantly lower than those of the control group over the same period. When FiO2 was equal to 1.00, PtO2, PaO2, SaO2 and O2ER in Zusanli acupoint, stomach and liver were increased compared with those when FiO2 was 0.21 in both groups, and the increase of PtO2 and O2ER in Zusanli acupoint, stomach and liver was more significant in the ARDS model group [PtO2 (kPa): Zusanli acupoint: 16.75±2.12 vs. 13.80±1.83, stomach: 16.45±1.33 vs. 13.35±1.25, liver: 16.43±1.45 vs. 13.45±1.36, O2ER: (36.14±0.97)% vs. (30.81±1.01)%]; the increase of PaO2, SaO2 and SvO2 was more significant in the control group [PaO2 (mmHg, 1 mmHg = 0.133 kPa): 682.02±50.32 vs. 159.32±40.17, SaO2: 1.00±0.00 vs. 0.98±0.01, SvO2: 0.69±0.01 vs. 0.63±0.03, allP < 0.05]. The indexes under FiO2 0.21 compared to those under FiO2 1.00 in the same group, it was shown that when FiO2 1.00, PvO2 was increased in the ARDS model group, but decreased in the control group, the difference between the two groups being statistically significant (mmHg: 36.00±2.83 vs. 42.50±1.70,P < 0.05). Besides, PtO2 in Zusanli acupoint was positively correlated to that in stomach (r = 0.963,P < 0.001).Conclusions When ARDS is under the condition of systemic oxygen delivery disorder, the demand of organ tissues for oxygen is significantly increased, but the oxygen utilization is impaired obviously, which is possibly related to the cellular mitochondrial dysfunction. There is good correlation between the tissue oxygen partial pressure of acupoint tissue and related organ tissue. The detection of oxygen in acupoint tissue has important guidance significance for monitoring the oxygen metabolism of related organ tissues.

BACKGROUND:Iron overload refers to excessive accumulation of iron in the body,which can cause pathological changes in various tissues.At present,the molecular mechanism and potential gene targets related to iron overload in osteoarthritis still need to be further studied and explored. OBJECTIVE:To analyze the key genes of iron overload in osteoarthritis by means of bioinformatics and verify them in animal experiments,so as to provide a new idea for preventing and treating osteoarthritis from the perspective of iron overload. METHODS:GEO database and GeneCards database were used to screen out genes associated with osteoarthritis and genes associated with iron overload.Then,the intersection of the two was taken to obtain a collection of genes commonly associated with osteoarthritis and iron overload.GO and KEGG enrichment analyses were used to screen the functions and pathways of these genes.To further investigate the interactions between these genes,a protein-protein interaction network was constructed and five computational methods of Cytoscape software were utilized to identify the Hub genes for iron overload in osteoarthritis.Finally,12 male Sprague-Dawley rats were divided into osteoarthritis group and normal group,with 6 rats in each group.A knee osteoarthritis model was established by the modified Hulth method in the osteoarthritis group.The expression of Hub genes in the knee joint of rats in each group was detected by PCR. RESULTS AND CONCLUSION:(1)A total of 51 genes associated with iron overload were identified in osteoarthritis.GO enrichment analysis showed that these genes were mainly involved in cytokine receptor binding,chemokine receptor binding,cytokine activity,growth factor receptor binding and oligosaccharide binding.(2)KEGG enrichment analysis showed that genes associated with iron overload in osteoarthritis was mainly involved in tumor necrosis factor signaling pathway and lipid and atherosclerosis signaling pathway.(3)The protein-protein interaction network was constructed,and five Hub genes of iron overload,intercellular cell adhesion molecule-1,tumor necrosis factor superfamily member 11,myelocytomatosis oncogene,janus kinase 2,and interleukin 6,were obtained by further analysis.Animal experiments verified that there were significant differences in the expression of the above Hub genes in the rat knee joint between the control group and the experimental group(P<0.05).(4)All these findings show that intercellular cell adhesion molecule-1,tumor necrosis factor superfamily member 11,myelocytomatosis oncogene,janus kinase 2,and interleukin 6 can be used as the Hub genes of iron overload in osteoarthritis,which are expected to become new targets for the prevention and treatment of osteoarthritis.