Expression of Peroxiredoxins and Pulmonary Surfactant Protein A Induced by Silica in Rat Lung Tissue

Silicosis is one of the most serious occupational diseases in China and dates back to centuries ago. In this study, we successfully established a rat model of silicosis by intratracheal silica injection for 28 days and determined hydroxyproline levels to evaluate collagen metabolism in lung homogenates. Oxidative stress status was evaluated by detecting catalase and glutathione peroxidase activities.

Interventional effect of hirudin on the expression of microtubule-associated protein 2 in peripheral tissue of hematom of model rats with acute intracerebral hemorrhage

BACKGROUND： It is suspected that dissociation, destruction or synthetic disorder of microtubule-associated protein 2 （MAP-2） may participate in secondary injury of intracerebral hemorrhage （ICH）, and the reason may be related to thrombin in high concentration after ICH; therefore, the mechanism should be studied further. OBJECTIVE： To explore the effect of hirudin on expression of MAP-2 in peripheral tissue of hematom after ICH and changes of water content in brain tissue and analyze pathogenesis of thrombin in secondary injury after ICH. DESIGN ： Completely randomized grouping design and controlled animal study SEn-ING ： Department of Neurology, the First Affiliated Hospital of Jilin University MATERIALS ： The experiment was carried out in the Neurological Laboratory of the First Affiliated Hospital of Jilin University from April 2003 to April 2004. A number of 80 healthy Wistar rats, of both genders, aged 3-4 months, weighing 250-350 g, were randomly divided into 8 groups： normal control group, 6-hour ICH group, 1-day ICH group, 2-day ICH group, 3-day ICH group, 7-day ICH group, 3-day hirudin group and 7-day hirudin group with 10 in each group. Five rats from each group were selected to measure their water content, and the others were undertaken immunohistochemical stain. Hirudin was produced by Sigma Company, USA, and MAP-2 rabbit-rat polyclonal antibody was provided by Fuzhou Maixin Biotechnology Company Limited. METHODS： ① Model establishing and grouping intervention： Rats in simple ICH group were collected their blood from tails and then inserted with 50 μL non-anticoagulant auto-arterial blood into the cauda of the putamen in right brain within 5 minutes. Rats in hirudin groups were inserted with 10 U hirudin （which was diluted with saline to 20 μL） into local hematom regions within 5 minutes, and the needle was pulled out after 10 minutes. Rats in normal control group were untouched. ② Water content in peripheral tissue of hematom： Based on the ratio between dry weight and wet weight, brain tissue at bleeding side and in right frontal lobe was selected to measure dry and wet weights so as to calculate the water content [（wet weight - dry weight） /wet weight] × 100%.③ Positive expression of MAP-2： Based on immunohistochemical stain, positive MAP-2 cells were regarded as neurons and they were buffy morphological. Positive rate of MAP-2 was calculated, i.e., percentage of positive cells in each sight to total cells in all sights. ④ Statistical analysis： Data among groups were compared with one-way analysis of variance, averages were compared with SNK-q test by each other, and relation between water content and MAP-2 was analyzed with linear regression technique. MAIN OUTCOME MEASURES： Changes of water content and MAP-2 expression in peripheral tissue of hematorn at various time points after ICH and intervention of hirudin. RESULTS： All 80 rats were involved in the final analysis. ①Water content： Water content was increased at day 1, reached peak at day 3 and decreased at day 7. It was （72.31±0.32）%, （77.42±0.53）%, （78.44±0.28）%, （74.10±0.13）%, （74.85±0.51）% and （70.07±0.36）%, respectively in 1-day, 2-day, 3-day and 7-day ICH groups and 3-day and 7-day hirudin groups, which was higher than that in normal control group （63.85±0.41, q=-4.684 3 to -7.262 0, P〈 0.05）; that in 2-day and 3-day ICH groups was higher than that in 7-day ICH group （q=-3.053 4, -3.727 0, P 〈 0.05）; and that in 3-day and 7-day ICH groups was higher than that in hirudin groups at the same time points （q=-2.965 6, -2.726 4, P 〈 0.05）. ②Positive expression of MAP-2： Positive expression of MAP-2 was decreased at 6 hours after ICH, reached the lowest value at day 3 and increased at day 7. Positive rate was （78.60±0.42）%, （60.56±0.74）%, （44.60±0.26）%, （25.45±0.85）%, （32.55±0.64）%, （37.69＋0.76）%, （41.75±0.68）%, respectively in 6-hour, 1-day, 2-day, 3-day and 7-day ICH groups and 3-day and 7-day hirudin groups, which was lower than that in normal control group [（96.50±0.33）%, q= -3.074 5 to -8.128 5, P 〈 0.05]. In addition, positive cells of MAP-2 disappeared plentifully at 3-7 days after ICH, stain of positive cells were light, and only stain of plasma was positive. That in 3-day and 7-day hirudin groups was higher than that in ICH groups at the same time points （q= -3.391 8, -2.967 9, P 〈 0.05）. Moreover, positive cells of MAP-2 was formed slightly but deeply stained. ③ Results of linear regression： Water content was negatively related to MAP-2 changes at 7 days after ICH （r= -0.894 9, P〈 0.01）, i.e., water content was increased with decrease of MAP-2 expression. CONCLUSION ： The deterioration of MAP-2 may be involved in the pathogenesis of thrombin within the first week after ICH, and the local administration of hirudin can protect neurons.

Maternal zinc deficiency impairs brain nestin expression in prenatal and postnatal mice

Effects of maternal dietary zinc deficiency on prenatal and postnatal brain development were investigated in ICR strain mice. From d 1 of pregnancy (E0) until postnatal d 20 (P20), maternal mice were fed experimental diets that contained 1 mg Zn/kg/day (severe zinc deficient, SZD), 5 mg Zn/kg/day (marginal zinc deficient, MZD), 30 mg Zn/kg/day (zinc adequately supplied, ZA) or 100 mg Zn/kg/day (zinc supplemented, ZS and pair-fed, PF). Brains of offspring from these dietary groups were examined at various developmental stages for expression of nestin, an intermediate filament protein found in neural stem cells and young neurons. Immunocytochemistry showed nestin expression in neural tube 10.5 d post citrus (dpc) as well as in the cerebral cortex and neural tube from 10.5 dpc to postnatal d 10 (P10). Nestin immunoreactivities in both brain and neural tube of those zinc-supplemented control groups (ZA, ZS, PF) were stronger than those in zinc-deficient groups (SZD and MZD). Western blot analysis confirmed that nestin levels in pooled brain extracts from each of the zinc-supplemented groups (ZA, ZS, PF) were much higher than those from the zinc-deficient groups (SZD and MZD) from 10.5 dpc to P10. Immunostaining and Western blots showed no detectable nestin in any of the experimental and control group brains after P20. These observations of an association between maternal zinc deficiency and decreased nestin protein levels in brains of offspring suggest that zinc deficiency suppresses development of neural stem cells, an effect which may lead to neuroanatomical and behavioral abnormalities in adults.

Retinal dopamine transporter in experimental myopia

OBJECTIVE: To investigate the distribution, changes and a possible role for retinal dopamine transporter (DAT) in experimental myopia in chickens. METHODS: Two-day-old chickens were divided into four groups. Chicken eyes were fitted with lenses of -10D,-20D and translucent goggles unilaterally. Normal eyes were used as controls. After 3 wk, all chickens were given an intramuscular injection of (125)I-beta-CIT 2beta-carbomethoxy-3beta-(4-iodophenyl)tropane and sacrificed two hours post injection. Retinal pigment epithelium (RPE) and the neural retina were obtained together or RPE was dissected out from the neural retina. Radioactive DAT from each specimen was assayed by gamma-counter. RESULTS: Retinal DAT was detected in RPE specimens rather than in the neural retina in all eyes. Radioactive DAT in myopic eyes was higher, compared with control eyes. CONCLUSIONS: Retinal DAT is mainly located in the RPE and may be involved in the formation of lens induced myopia (LIM) and form deprivation myopia (FDM). These methods may provide a new approach for further studying the role of the dopamine system in experimental myopia.

Nestin expression and proliferation of ependymal cells in adult rat spinal cord after injury

OBJECTIVE: To determine cell proliferation and nestin expression in the ependyma of adult rat spinal cord after injury. METHODS: Rat spinal cord injury models were established by aneurysm clip compression, and nestin expression and proliferation of ependymal cells at different times were shown with pathological and immuno-histochemical staining. RESULTS: Ependymal cells adjacent to the injured site demonstrated a dramatic increase in nestin expression 24 hours after compression. Proliferating cell nuclear antigen was positive, and significant proliferation was observed after 7 days. Nestin expression was down regulated as time went by. CONCLUSION: Normally quiescent mature ependymal cells appear to revert to an embryonic state in response to spinal cord injury.