ObjectiveTo study the influence of hemin on blood pressure of intermittent hypoxic rats and investigate the mechanism of hypertension caused by intermittent hypoxia.MethodsTwenty-four male SD rats were randomly divided into a hemin group, an intermittent hypoxia group (IH group) and a normal group. Thirty minutes after intraperitoneal injection of hemin, the rats in the hemin group were exposed to intermittent normobaric hypoxic environment (8 h/d). The rats in the IH group were intraperitoneal injected with normal sodium and then exposed to the same environment (8 h/d). The rats in the normal group were intraperitoneal injected with normal sodium and placed in the glass box. The three groups were bred in the same condition. Thirty-five days later, the mean carotid artery pressure (mCAP) of the rats was measured and their plasma carbon monoxide (CO) level was measured by Chalmer’s method. Reverse transcription polymerase chain reaction was performed to detect the levels of heme oxygenase-1 (HO-1) mRNA expression in lung, liver, spleen, kidney and other organs. The expression of HO-1 protein in the organs was detected by immunohistochemistry.ResultsThe mCAP in the IH group was significantly higher than the hemin group and the normal group (P<0.05), and was higher in the hemin group than the normal group (P<0.05). The concentration of plasma CO in the hemin group was higher than the IH group and the normal group (P<0.05). There was no significant difference in plasma CO between the IH group and the normal group (P>0.05). The expression of HO-1 mRNA of lung, liver, spleen and kidney in the hemin group and the IH group was higher than the normal group (P<0.05), and was higher in the hemin group than the IH group (P<0.05). The relationship between mCAP and HO-1 mRNA showed a curvilinear trend. The quadratic curve fitting equation was Y=39.715+446.640X-334.353X2.ConclusionsIntermittent hypoxia can cause hypertension in rats. The HO-1 expression is increased in hypoxic rats, but the plasma CO does not increase significantly. As an inducer of HO-1, hemin can increase the expression of HO-1 and CO in hypoxic rats, then lower their blood pressure to some extent.
ObjectiveTo investigate the expression of histone deacetylase 2 (HDAC2) in animal model of benign tracheal stenosis, and explore the mechanism of HDAC2 in development of tracheal stenosis.MethodsEighteen rabbits were randomly divided into a blank control group, a model group, and an erythromycin group, with 6 rats in each group. The model group and the erythromycin group underwent tracheostomy, the inner wall of trachea was brushed back and forth with a nylon brush for more than 20 times to induce benign tracheal stenosis. From 7 days before surgery to 9 days after surgery, the model group received gavage with saline, the erythromycin group received gavage with low-dose erythromycin in dose of 15 mg·kg–1·d–1, and the control group did not receive any treatment. On the 10th day after operation, all the rabbits were sacrificed and the trachea was cut to measure the tracheal stenosis. RNA and protein were extracted from the granulation tissue in the stenosis and the relative mRNA expressions of HDAC2, interleukin (IL)-6 and IL-8 in the granulation tissue were detected by real-time fluorescence quantitative PCR. The relative expression of HDAC2 protein was detected by Western blot.ResultsCompared with the blank control group, the tracheal stenosis in the model group was more obvious [(84.60±1.14)% vs.(27.00±6.44)%], the mRNA and protein expressions of HDAC2 were decreased (0.29±0.07 vs. 1.00±0.00, 0.20±0.02 vs. 0.49±0.04), the mRNA expressions of IL-6 and IL-8 were up-regulated (4.22±0.67 vs. 1.00±0.00, 162.72±23.23 vs.1.00±0.00). Compared with the model group, tracheal stenosis in the erythromycin group was relieved [(64.00±12.25)% vs. (84.60±1.14)%], the mRNA and protein expressions of HDAC2 were increased (0.42±0.14 vs. 0.29±0.07, 0.43±0.01 vs. 0.20±0.02), the mRNA expressions of IL-6 and IL-8 were decreased (0.72±0.24 vs. 4.22±0.67, 130.22±7.93 vs. 162.72±23.23). All the differences were statistically significant (all P<0.05). The Pearson correlation coefficient between tracheal stenosis and HDAC2 mRNA relative expression was –0.96 (P<0.05).ConclusionsThe down-regulation of HDAC2 expression in model of benign tracheal stenosis is related to the occurrence and development of tracheal stenosis. The low dose of erythromycin may be used to treat benign tracheal stenosis by up-regulating expression of HDAC2 and thus inhibiting the inflammatory disorder during tracheal injury repair.