Objective: To investigate the role of surfactant associated protein-A (SP-A) in the development and progression of silicosis, and its mechanism. Methods: Homozygous and heterozygous mice of SP-A knockout of specific pathogen free (SPF) grade were selected for mating, and mice with SP-A^-/- genotype were selected for subsequent experiments. SP-A wild-type (SP-A^+/+) and SP-A^-/- mice were divided into SP-A^+/+ control group, SP-A^-/- control group, SP-A^+/+ silicosis group and SP-A^-/- silicosis group with six mice in each group by random number table method. Mice in both silicosis groups were given 20.0 μL 250 g/L silica suspension by tracheal exposure, and mice in both control groups were injected with 0.9% sodium chloride solution at the same volume. On the 28th day after modeling, mice were sacrificed. Lung tissues were used for lung histopathology examination. The apoptosis of alveolar type Ⅱ epithelial cells of mice was detected by TUNEL method. The mRNA expression of B-lymphoblastoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), cysteinyl aspartate specific proteinase (Caspase)-3 and Caspase-9 in lung tissues of mice was detected by quantitative real-time polymerase chain reaction. Results: The histopathological result of mice showed that thickened alveolar septum, scattered silicon nodule and collagen fiber formation were observed in the mice lungs of SP-A^+/+ silicosis group, and a large number of inflammatory cells were observed in silicosis nodule, after exposure to silica dust. SP-A^-/- silicosis group resulted in a more severe pulmonary inflammation and interstitial fibrosis compared to SP-A^+/+ silicosis group. The apoptosis of alveolar type Ⅱ epithelial cells and the mRNA relative expression levels of Bax, Caspase-3 and Caspase-9 in lung tissues of mice in each silicosis groups were increased compared with their control groups (all P<0.05). The above four indexes of mice in SP-A^-/- silicosis group were higher than those in SP-A^+/+ silicosis group (all P<0.05). There was no significant difference in the expression of Bcl-2 mRNA in lung tissues of these four groups (P>0.05). Conclusion: Knockout of SP-A can aggravate inflammation and pulmonary fibrosis in silicosis model mice, and promote apoptosis of alveolar type Ⅱ epithelial cells. The mechanism may be related to the Bcl-2/Bax/Caspase-3 signaling pathway which affects the apoptosis of mitochondrial pathway.

Objective To explore the applied effect of families synchronous health education on compliance with intermittent catheterization in patients with spinal cord injury and bladder voiding dysfunction. Methods A total of 60 patients with spinal cord injury caused bladder voiding dysfunction were randomly divided into observation group and control group in admitted chronological order. Patients in control group were given routine nursing; experimental group on the basis of conventional nursing, were applied families synchronous health education throughout the whole process of hospitalization and discharge follow-up. After 30 and 60 days′ self-intermittent catheterization, two groups′ urinary tract management of cognition, satisfaction, compliance and complications were observed and statistically analyzed. Results After 30 and 60 days′ self-intermittent catheterization, the observation group′ urinary tract management of cognition and satisfaction score were higher than those of the control group( P<0.01) . About the compliance, on the 30th day, two groups′urethral catheterization in time, volume of water intake, correctly evaluation residual urine volume and correctly bladder function training had no statistically difference ( P>0. 05); the observation group′s properly adjusting time and correctly operation of urethral catheterization was higher than the control group(P<0.05); on the 60th day, all kinds of aspects of observation group were better than the control group( P<0.05) . About the complication, on the 30th day, the urinary infection rate of observation group was lower than that of the control group( P<0.05);there were no difference on the rate of cystolith and urinary mucosa bleeding of two groups( P>0.05);on the 60th day, the rate of cystolith and urinary mucosa bleeding of the observation group were lower than those of the control group ( P<0. 05 ); two groups′ incidence of bladder calculi had no difference ( P>0. 05 ) . Conclusions Families synchronous health education actively, can improve the compliance of patients with intermittent catheterization and reduce related complications, thus improve the patients′satisfaction.

Objective To investigate the effects and mechanisms of silica dust on the apoptosis of alveolar epithelial cell (AEC) through in vitro and animal experiments. Methods i) In vitro experiment. A549 cells were stimulated with 100 mg/L silica suspension for 0, 12, 24 and 48 hours. The cell apoptosis rate was detected by flow cytometry. ii) Animal experiment. Specific pathogen-free male C57BL/6 mice were randomly divided into control, 14-day, 28-day, and 56-day groups, with five mice in each group. The mice in the control group were sacrificed at 56 days after being treated with 40.0 μL 0.9% sodium chloride solution, and the mice in the last three groups were sacrificed at 14, 28 and 56 days after being treated with 40.0 μL silica suspension with a mass concentration of 125 g/L via tracheal exposure method. The lung tissues of mice were collected to measure lung organ coefficients. Masson staining was used to detect the degree of pulmonary fibrosis, and Ashcroft scores were evaluated. The apoptosis of AEC in mice was observed by TUNEL immunofluorescence assay. iii) The mRNA relative expression of apoptosis-related genes in A549 cells and mouse lung tissue was detected using reverse transcription and real-time fluorescence quantitative polymerase chain reaction. Results i) In vitro experiment. The apoptosis rate of A549 cells increased with longer silica exposure (all P<0.05). The relative expression of B cell lymphoma-2 (BCL-2) mRNA in A549 cells in 24 h group and 48 h group decreased (both P<0.05), and the relative expression of BCL-2 associated X protein (BAX) mRNA increased (both P<0.05), compared with 0 h group. The mRNA relative expression of caspase (CASP) -3 and CASP-9 in A549 cells increased with longer silica exposure (all P<0.05). ii) Animal experiment. The lung organ coefficients and Ashcroft score in mice progressively increased (all P<0.05), the degree of pulmonary fibrosis was gradually aggravated, and TUNEL positive cells in lung tissue were gradually increased, while Bax, Casp-3 and Casp-9 mRNA relative expression increased with longer silica exposure (all P<0.05). Conclusion Silica dust may cause pulmonary fibrosis by inducing apoptosis of AEC, with a time-dependent effect. The mechanism may be related to the effect of silica dust on mitochondrial apoptosis through Bcl-2/Bax/Caspase-3 signaling pathway.

ObjectiveTo investigate the relationship between plasma surfactant protein⁃A （SP⁃A） expression level and silicosis progression， and to provide early evidence for exploring whether SP⁃A can be used as a biomarker for clinical monitoring of silicosis disease progression. MethodsWe recruited 187 silicosis patients in Guangdong Province hospital for occupational disease prevention and treatment between November， 2019 and November，2020. Their peripheral venous blood samples were collected for the plasma isolation. The level of pulmonary SP⁃A was detected by enzyme-linked immunosorbent assay. ResultsThere was a statistically significant difference in the level of SP⁃A among the silicosis groups （P<0.05）， and the plasma SP-A level of the silicosis patients in stage Ⅲ was higher than that in stage Ⅰ and stage Ⅱ （P<0.05）. Smoking had effect on plasma SP⁃A levels， Age， working years and drinking had no effect on plasma SP⁃A levels. ConclusionThe expression level of SP⁃A in the plasma of silicosis patients is increased， which has a certain correlation with the disease stage， and plays a certain early warning role in the occurrence and development of silicosis， and may be a potential biomarker for the diagnosis and prognosis of silicosis.