| Objective: Sepsis may be induced by the overreaction to infections, trauma and so on. It's severe systemic inflammatory response syndrome (SIRS). When sepsis is progressed, it may cause the dysfunction of organs and tissues, called severe sepsis or septic shock. The morbidity and mortality of sepses are higher, multi-organ dysfunction syndrome is the main reason for its high mortality. In recent years, despite fluid resuscitation, broad-spectrum antibiotics, advanced life support methods to promote the implementation of standard treatment, its still no significant improvement in mortality. It is still critically illness, and one of the major causes of death. So the diagnosis and treatment of sepsis or septic shock are important tasks of modern medical workers.The hypothalamus - pituitary - adrenal axis (HPAA) stress in the body play an important role, when the body suffered serious infection or trauma, a series of neuroendocrine and immune responses to HPAA activation and eventually can cause a lot of increasing of secretion of cortisol in order to protect the body against inflammation and excessive immune response. The increasing level of cortisol in sepsis mainly was caused by the higher levels of cytokines in blood on the condition of severe infections. Cytokine stimulate the HPAA and induced over secretion of corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) or directly stimulate the adrenal cortex leading the significantly increased cortisol level. In addition, inflammatory cytokines cause the increasing of cortisol levels in tissues through changes in peripheral cortisol metabolism. Research on the hypothalamus - pituitary - adrenal axis (HPAA) has important role for the management of sepsis and septic shock.Despite significant increasing of cortisol concentrations in the stress condition in some patients, but the increased extent or the lasting time are still unable to maintain the body's need. This performance is the so-called "relative insufficiency of cortisol secretion", we described this phenomenon as relative adrenal insufficiency (relative adrenal insufficiency, RAI). RAI can also decrease the stress response of patients and deteriorate the progress of sepsis, affect the treatment and prognosis. However, based on a clinical manifestation alone is difficult to diagnose RAI. In the present, there is not a diagnostic standard for RAI. Random cortisol concentration determination and adrenocorticotropic hormone (ACTH) stimulation test has become a key tool.RAI prompt the lack of the HPA axis response to sepsis infection or disorder, and thus offers a possibility to the use of exogenous glucocorticoid replacement therapy. But currently there is still much difference and has not been a uniform standard for how to use glucocorticoid reasonably.Evidence-Based Medicine confirmed that high-dose application of corticosteroids in patients with severe sepsis not only fail to reduce mortality, but increase the chances of infection, although the physiological dose of adrenal glucocorticoids in the treatment of sepses to be respected, low-dose hormone replacement therapy for the septic shock also failed to be confirmed in recent clinical study.In this study, monitoring the hypothalamus - pituitary - adrenal axis (HPAA) hormones (ACTH, cortisol), and pro-inflammatory / anti-inflammatory factor (TNF-α, IL-6) levels in early septic shock in rats inflammatory factors and changes in HPAA analysis, offering the appropriate basis for the study of RAI and for the development of relevant diagnostic criteria and clinical application of hormone replacement therapy in sepsis.Method:1 Animals and groups: 56 healthy male adult wistar rats were choosed which weighing from 250 to 300 grams, and randomly divided into two groups: control group (n = 16) and the shock group (n = 40). Shock group were divided into 8 groups: after the began of model building 3h, 6h, 9h, 12h, 15h, 18h, 21h, 24h. And the measure time of 3h group is 0:00 am. The other time groups followed by the subsequent measurement time points and so on. Blood ACTH, cortisol, TNF-α, IL-6 levels were measured in shock groups. In shock group, 5 rats were selected randomly to measure at each time point. Measurement of blood ACTH and cortisol were made at the parallel moment in control group with the shock groups.2 Model making: Before the experiment, rats were weighed , 10% urethane solution was injected (1ml/kg) for anesthesia, right carotid artery catheter connected BL-420E + experimental system of biological function to monitor mean arterial pressure, stability for 15mins and record the basic blood pressure. After intraperitoneal injection of lipopolysaccharide (LPS) 10mg/kg, mean arterial pressure were monitored, when the mean arterial pressure reduced to 20% level (compared with baseline) and last for more than 15mins. Same method was used in control groups instead of LPS replacement with normal saline. The changes of blood pressure were recorded through the entire whole experiment courses.3 Test of blood samples: Indicators of HPA-related (cortisol, ACTH) were measured in both model groups and the control groups at each time point and TNF-αand IL-6 were measured in model groups. Serum specimens from each sample was centrifuged and saved in -70℃. Serum cortisol and plasma ACTH were tested by radioimmunoassay, TNF-αand IL-6 were tested by immunosorbent assay (ELISA).Results:1 ACTH measurement: AT 3h, ACTH measurement in the shock group value were (16.65±0.77), in the control group were (19.78±0.64); at 6h, ACTH measurement in the shock group were (3.42±0.88), in the control group were (15.25±0.59); at 9h, ACTH measurement in the shock group were (6.87±0.72), in the control group were (20.51±1.34); at 12h, ACTH measurement in the shock group were (9.80±0.49), in the control group were (9.69±0.27); at 15h, ACTH measurement in the shock group were (9.47±0.52), in the control group were (11.19±0.49); at 18h, ACTH measurement in the shock group value were (12.78±0.54 ), in the control group were (15.56± 0.74); at 21h, ACTH measurement in the shock group value were (11.04±0.17), in the control group were (14.89±0.18); at 24h, ACTH measurement in the shock group were (10.67±0.34), in the control group were (11.42±1.91). The result of ACTH levels in shock group and control group tested using analysis of variance , F value 14.53, P <0.05, there were significant differences between the two groups.Time point of each shock group and the control group, ACTH levels tested using analysis of variance (table 2), found in 3h, 6h, 9h, 15h, 18h, 21h of the F-values were 25.34, 291.07, 374.85, 15.87, 35.78, 703.77, 0.98. P-value is much smaller than 0.05, there were significantly different between each shock group and control groups. The F-value of 12h and 24h, respectively were 0.08 and 0.98. No statistically significant.2 Measurement of cortisol: At 3h, the cortisol measurements in the shock group value were (1099.26±19.09), in the control group were (40.24±0.71); at 6h, the cortisol measurements in the shock group value were (849.44±22.53), in the control group were (54.44±0.77); at 9h the cortisol measurements in the shock group value were (895.44±4.34), in the control group were(55.10±0.33); at 12h, the cortisol measurements in the shock group value were (1055.5±28.2 ), in the control group were (79.87±0.76); at 15, the cortisol measurements in the shock group value were (710.38±5.9), in the control group were (57.19±0.76); at 18, the cortisol measurements in the shock group value were (1139.82±24.48), in the control group were (68.41±0.81); at 21h, the cortisol measurements in the shock group value were(717.01±4.57), in the control group were (99.81±1.04); at 24h, the cortisol measurements in the shock group value were (690.8±8.16), in the control group were (66.5±0.8). Cortisol levels in Shock group and the control group tested using analysis of variance (table 1), F value is 410.79, P value is much smaller than 0.05, showing a significant difference between the two groups. The two groups at each time point using analysis of variance test cortisol, Every P values are much smaller than 0.05, there were significantly different between the each two groups. 3 TNF-αmeasurement: Shock group at 3h of TNF-αmeasured value were (74.97±5.85), 6h measured value were (87.69±2.28), 9h measured value were (91.88±3.46), 12h measurement value were (112.46±5.26) , 15h measured value were (114.81±3.91), 18h measured value were (118.85±2.09), 21h measured value were (119.28±0.87), 24h measured values were (109.19±5.35). In addition, at 12h, in the control group of TNF-αmeasured value were (69.83±1.37). The 12h control group compared to the shock group (table4), F = 8.6, P = 0.006 <0.05. There were statistically significant. The 12h control group compared to 12h shock group (table5), F = 115.41, P value is much smaller than 0.05. There were a significant different between the two groups.4 IL-6 measurement: Shock group at 3h of IL-6 measured value were(418.3±27.3), at 6h measured value were (461.1±41.4), at 9h measured value were (587.9±23.1), at 12h measured value were (669.3±37.8) , at 15h measured value were (666±96.9), at 18h measured value were (729.6±33.4), at 21h measured value were (734.7±45.9), at 24h measured value were (788.35±21.3). In addition, at 12h, in the control group TNF-αmeasured value were (788.35±21.3). The 12-hour control group compared to the shock group (table4), F = 25.32, P <0.05, statistically significant. The 12-hour control group and 12-hour shock group (table5), F = 331.3, P value is much smaller than 0.05. There were a significant different between the two groups.Conclusion:1 In the early time of septic shock, disorder of the hypothalamus - pituitary - adrenal axis (HPAA) was existed and normal circadian rhythm was changed.2 HPAA rhythm disappeared suggested that HPAA in severe infections had been seriously affected; this reflecting the HPAA in stress played a very important physiological role.3 In the early time of septic shock, pro-inflammatory / anti-inflammatory response occurred, suggesting that the infection is an important factor for the change of the hypothalamus - pituitary - adrenal axis (HPAA), this change along with the occurrence of infection, and is a progressive proceses.4 The concentration of cortisol was increased significantly in septic shock and ACTH secretion inhibited by feedback increased cortisol, indicating a relative adrenal insufficiency in the disease process.
|
PDF Full Text Request