Protective effects of IGF-1 on cortical nerve cells of neonatal rats under oxidative stress / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the protective effects of insulin-like growth factor-1 (IGF-1) on the nerve cells of neonatal rats under oxidative stress.</p><p><b>METHODS</b>Primary cortical neurons, oligodendrocytes, and astrocytes from newborn rats were cultured. An oxidative stress model was established with different concentrations of H2O2 (0-60 μmol/L); the degree of damage of nerve cells was evaluated by lactate dehydrogenase assay, and the viability of nerve cells was tested by MTT assay. An oxidative stress model was established with different concentration of H2O2 (0-80 μmol/L). Expression of Akt/p-Akt (Ser473) in neurons was measured by Western blot before and after IGF-1 (25 ng/mL) administration.</p><p><b>RESULTS</b>Compared with those not treated with H2O2, the cortical neurons, oligodendrocytes, and astrocytes treated with different concentrations of H2O2 for 24 hours showed increased damage and decreased cell viability; compared with oligodendrocytes and astrocytes, neurons showed significantly more changes (P<0.01). Compared with those not treated with H2O2, the cortical neurons treated with different concentrations of H2O2 for 5 minutes showed a significant decrease in p-Akt (Ser473) level (P<0.01), which was dependent on the concentration of H2O2. For the neurons treated with low-concentration H2O2, the addition of IGF-1 could reverse the inhibition of Akt phosphorylation, eliminating the difference in p-Akt level compared with the neurons not treated with H2O2, (P>0.05); however, it had no significant effect on the inhibition of Akt phosphorylation by high-concentration H2O2, and the treated neurons still had a lower p-Akt level than untreated neurons (P<0.01 for all). For the cortical neurons that had been treated with different concentration of H2O2 for 1 hour, the addition of IGF-1 (25 ng/mL) could eliminate thedifference in p-Akt level between the treated neurons and untreated neurons (P>0.05).</p><p><b>CONCLUSIONS</b>Cortical neurons are more sensitive to oxidative stress induced by H2O2 than other nerve cells. IGF-1 has protective effects on cortical nerve cells under oxidative stress.</p>

Retinoic acid diminished the expression of lung tissue matrix metalloproteinase-2 and matrix metalloproteinase-9 in hyperoxia-exposed premature rats through regulating mitogen-activated protein kinases / 中华儿科杂志

<p><b>OBJECTIVE</b>To further investigate the protective effect of retinoic acid (RA) on hyperoxia induced lung injury and the role of RA as a modulator on mitogen-activated protein kinases (MAPKs).</p><p><b>METHODS</b>Establishment of hyperoxia (85%) induced lung injury model of premature Sprague-Dawley (SD) rats: 21 d gestational age SD rat's fetuses (term = 22 d) were delivered by hysterectomy. Within 12 - 24 h after birth, the premature rat pups were randomly divided into 4 groups: Group I, air-exposed control group; Group II, hyperoxia-exposed group; Group III, air plus RA-exposed group, Group IV, hyperoxia plus RA-exposed group. Group I and III were remained in room air, and group II and IV were placed in 85% oxygen. The pups in Group III and IV were injected with RA (500 microg/kg, every day) intraperitoneally. The entire lung tissues of premature rat pups were collected at 4 d, 7 d and 14 d. The mRNA levels of MMP-2 and MMP-9 were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). MMP-2 and MMP-9 activities were measured by zymography. Western blot was used to detect phosphorylated and total nonphosphorylated form of ERKs, JNKs and p38.</p><p><b>RESULTS</b>Exposure to oxygen for 4 d, 7 d, and 14 d resulted in increased mRNA levels of MMP-2 and MMP-9 compared with air-exposed control group (P < 0.01 for all). The mean protein levels of active MMP-2 and pro/active MMP-9 after exposure to O2 were higher than air control groups on each experimental day (P < 0.01 or < 0.05). The phosphorylated ERK1/2, JNK1/2 and p38 proteins in hyperoxia-exposed group increased markedly compared with air-exposed control group (P < 0.01 for all). The pups treated with RA in the hyperoxic environment expressed significantly lower mRNA levels of MMP-2 and MMP-9 than the hyperoxic control pups on each experimental day (P < 0.05 for all). The levels of active MMP-2 and pro/active MMP-9 decreased to a different degree after RA treatment in hyperoxia exposure rat pups. In addition, RA treatment led to a decrease of p-JNK1/2 and p-38 (P < 0.01 for all) protein levels and a further elevation of p-ERK1/2 compared with hyperoxia-exposed group.</p><p><b>CONCLUSION</b>Hyperoxia exposure elevated the expression of MMP-2 and MMP-9 markedly, which played a role in oxygen-induced lung injury. RA could have a protective effect on hyperoxia induced lung injury by decreasing active levels of JNK and p38, which subsequently reduce the expression and activation of MMP-2 and MMP-9.</p>

Diagnostic Value of Pathogenic Detection on Acute Respiratory Infection in Children by Multi-IgM Investigation / 实用儿科临床杂志

Objective To investigate the pathogens of acute respiratory infection of children.Methods A total of 159 children with acute respiratory infection who were hospitalized in our department from August 2005 to January 2006 were involved in this study.The serum IgM antibody of 18 pathogens were detected by indirect immunofluorescence test.The 18 pathogens included respiratory syncytial virus(RSV),adenovirus(ADV),influenza A(H1N1,H3N2)and B viruses,parainfluenza viruses(PIV) type 1,2,3 and 4,coxsackie virus B1(CBV1),coxsackie virus A7(CAV7),echovirus(ECHO7),haemophilus influenzae(HI),klebsiella pneumoniae(KP),bordetella pertussis(BP),bordetella parapertussis(BPP) and legionella pneumophila serotype 1 and 12.Results The evidence of specific IgM was obtained in 103 of 159 patients(64.78%).Influenza A was found in 66 cases(64.08%),influenza B in 49 cases(47.57%),enterovirus in 26 cases(25.24%),RSV in 18 cases(17.48%),PIV in 11 cases(10.68%),and co-infection in 66 cases(64.08%),1/ 3 of them were co-infected with influenza A and B.Conclusions Viruses are the most common agents of acute respiratory infection.Influenza virus is predominant among them.