Glucocorticoid receptor expression on acute lung injury induced by endotoxin in rats.

BACKGROUND: In cases of severe sepsis and septic shock, a series of pathophysiological changes lead to multiple organ dysfunction syndrome. This study aimed to investigate the expression of glucocorticoid receptor mRNA in the rat lung following endotoxin (LPS) induced shock. METHODS: Totally 56 SD rats were randomly divided into 4 groups: LPS shock group (n=16), LPS+vasoactive intestinal peptide group(VIP) group, (n=16), LPS+VIP+ glucocorticoid (GC) group, (n=16),and control group (n=8). LPS shock was induced by intravenous injection of LPS (10 mg/kg) in rats. Within 15 minutes after LPS injection, rats in the treatment groups received VIP (5 nmol/kg) or VIP and methylprednisolone (3 mg/kg). The control group was given normal saline instead of LPS. The rats of the four groups were sacrificed at 6 hours,24 hours after injection respectively, and the lung tissues were collected. Pathological changes of the lungs were examined by light microscopy and electron microscopy. GRmRNA expression in the lung tissues was evaluated by RT-PCR. RESULTS: In the LPS shock group, lung histopathology demonstrated destruction of the alveolar space,widening of the inter-alveolar space, inflammatory cell infiltration and interstitial edema. However,pathological changes in the LPS+ VIP group and LPS+ VIP+GC group were milder than those in the LPS shock group. Six hours after LPS injection, GR mRNA expression was down-regulated in the LPS group (0.72± 0.24) and LPS+ VIP group (0.88±0.27) (P<0.05) as compared with the control group (1.17±0.22). The LPS shock group showed a more significant down-regualtion than the LPS+VIP group, but the difference was not statistically significant (P>0.05). In contrast, GRmRNA expression in the LPS+ VIP+GC group was significantly up-regulated at 6 hours and further at 24 hours (1.45±0.32 and 1.91±0.46 respectively) (P<0.05). CONCLUSION: GrmRNA expression decreased in LPS induced lung injury in rats. Combined treatment with VIP and GC mitigated lung injury ang inflammation. The mechanism may be related to up-regulation of GR mRNA expression.

[Impact of endogenous inflammation caused by adenovirus as a vector in gene therapy: experiment with mice models of acute lung injury].

OBJECTIVE: To evaluate the impact of endogenous inflammation caused by adenovirus as a vector of gene therapy on mouse model of acute lung injury (ALI). METHODS: Black C57/B6 mice randomly divided into 4 research groups: (1) adenovirus encoded-lacZ gene treatment group (AdLacZ): n=43; (2) three control groups: (1) before 100% O2 inhalation (Con): n=26; (2) 100% O2 inhalation with TBS + PBS treatment (PBS): n=36; (3) 100% O2, inhalation without treatment (no treatment): n=33. AdLacZ reagent through intranasal administration to infect mice lungs at 48h before 100% O2 inhalation to induce ALI mouse model, which companies by mice survival rates recorded. beta-gal protein activity in lung was detected to show the level of LacZ DNA transgenic protein activity;meanwhile, the indices of lung wet/dry ratio and bronchial alveolar lavage liquid (BALF) analysis with protein concentration and cell classification were detected. RESULTS: The method of adenovirus-mediated gene therapy with intranasal administration resulted in LacZ DNA transgenic protein activity to keep effective highly expression in lung, and the expression level maintained 2-fold increasing even after 72 h of O2 inhalation compared to that before O2 inhalation (3.688 U/mg vs. 1.589 U/mg); AdLacZ mice had more subjective to O2 inhalation compared to other groups, the 50% mice survival time of this group was shorter compared to that of the PBS group [(86 +/- 3) h vs. (94 +/- 7) h]; also in AdLacZ group, the level of nucleated cell counting in BALF was statistically higher compared to other groups at 48 h of O2 inhalation, which following with 50%-level decreased within anther 24 h O2 inhalation; on the contrary, the level of lung wet/dry ratio and protein concentration in BALF didn't show remarkably decreasing. CONCLUSION: The endogenous inflammation caused by adenovirus as a vector in ALI gene therapy is temporary and rapidly weaken after getting a peak, however, enough attention still should be paid attention when evaluating the effect of gene therapy.

[Adrenal function evaluation using ACTH stimulation test in children with sepsis and septic shock].

OBJECTIVE: Sepsis and septic shock remain a common problem that results in significant mortality and morbidity in pediatric intensive care units (PICU). According to literature, the use of more physiologic steroid replacement therapy is associated with hemodynamic and survival benefits in adult patients with relative adrenal insufficiency (RAI) and catecholamine-resistant septic shock. But little information is available in children. The aim of the current prospective study was to determine the prevalence of adrenal insufficiency in children with sepsis and septic shock using a low-dose adrenocorticotropic hormone (ACTH) stimulation test (1 microg/1.73 m2) in children. METHODS: The authors performed cortisol estimation at baseline and after low-dose (1 microg/1.73 m2) ACTH stimulation at 30 mins in children during the first 24 hours in patients with sepsis or septic shock admitted to our PICU. Adrenal insufficiency was defined as a response < or = 90 microg/L. Absolute adrenal insufficiency (AAI) was further defined as baseline cortisol (T0) < 200 microg/L and RAI insufficiency by T0 > or = 200 microg/L. RESULTS: Sixty-two consecutive cases with sepsis and septic shock admitted to PICU of Shanghai Jiaotong University Affiliated Children's Hospital from April, 2006 to March, 2007. The median age was 37.6 months (range, 2 - 168 months), and their gender distribution was 42 (67.7%) males and 20 (32.3%) females, 53 cases had sepsis (85.5%) and 9 had septic shock (14.5%). The mean pediatric critical illness score (PCIS) was 79.3 +/- 9.2 and median pediatric risk of mortality score (PRMSIII) 11.3 (5 - 19), respectively. Overall mortality of sepsis and septic shock was 27.42%. The evaluation of adrenal insufficiency was conducted as follows. (1) The mean cortisol levels at baseline (T0) and 30 mins after ACTH stimulation (T1) were (318.6 +/- 230.4) microg/L, (452.3 +/- 230.7) microg/L and (454.7 +/- 212.7) microg/L, (579.3 +/- 231.9) microg/L in patients with severe sepsis and septic shock group, respectively. There were no significant difference between the two groups (P > 0.05). (2) The proportion of patients with adrenal insufficiency in the study population was 40.3% as defined by a response < or = 90 microg/L post test. The proportion of patients with adrenal insufficiency in sepsis and septic shock were 39.6% and 44.4%, respectively (chi2) = 0.073, P > 0.05). (3) The serum T0 and T1 levels were (320.5 +/- 223.9) microg/L, (462.3 +/- 212.0) microg/L and (384.3 +/- 258.3) microg/L, (500.7 +/- 470.6) microg/L, respectively, and the proportion of patients with adrenal insufficiency were 37.8% and 47.1% in the survivors and the dead (P > 0.05). The levels of T0 and T1 were related to the PCIS (P < 0.05). The morbidity of adrenal insufficiency was not related to the PCIS, PRISMIII, and number of organ that developed functional insufficiency (P > 0.05). CONCLUSIONS: Adrenal insufficiency may occur in patients with sepsis and septic shock in children. ACTH stimulation test may be helpful to determine whether corticosteroid therapy has a survival benefit in patients with relative adrenal insufficiency. A low-dose ACTH stimulation test can be used to evaluate the adrenal function status of severe sepsis and septic shock in children.