摘要
目的肺表面活性物质蛋白D(SP-D)被认为是急性肺损伤(ALI)和急性呼吸窘迫综合征(ARDS)有价值的生物指标,但在急性肺损伤早期,肺组织SP-D的变化特征仍不清楚.该研究旨在探究脂多糖(LPS)诱导的SD幼鼠急性肺损伤时SP-D,SP-D mRNA的时序变化及肺泡Ⅱ型上皮细胞及板层小体的超微结构的变化.方法腹腔内注射LPS建立急性肺损伤模型.注射后6,12,24,36,48,72 h各处死8只大鼠.Western blot和RT-PCR方法测定肺组织SP-D和SP-D mRNA的含量.透射电子显微镜研究肺泡Ⅱ型上皮细胞超微结构的变化.结果LPS注射12 h后SP-D和SP-D mRNA含量均开始下降.SP-D mRNA于注射LPS后24～36 h降到最低.SP-D在48 h达最低点.透射电镜显示急性肺损伤组板层小体出现多样变形,特别是在注射后48 h.LPS导致板层小体的体积增大、数量减少,伴有大量空泡样变.结论在LPS诱导的急性肺损伤的早期SP-D的波动变化呈时间依赖性.肺组织SP-D在48 h时水平最低,此时伴有肺泡Ⅱ型上皮细胞严重的多形性变.在ALI发病初期,肺组织低水平的SP-D与较差的临床预后有关.
Objective Pulmonary surfactant protein-D （SP-D） is regarded as a valuable biomarker in acute lung injury （ALI） and acute respiratory distress syndrome （ARDS）, but the alterations of SP-D in lung tissues in the early course of ALI remain unknown. This study was designed to explore the temporal fluctuations of SP-D and SP-D mRNA in young rats with ALI induced by lipopolysaccharide （LPS） , as well as the alterations of ultrastructures of alveolar type Ⅱ （ATⅡ） cells. Methods Rat ALI models were established by intraperitoneal injection of LPS （4 mg/kg）. The rats were sacrificed at 6, 12, 24, 36, 48 and 72 hrs after LPS injection （8 rats each time point）. Western blot and RT-PCR were employed to detect the contents of SP-D and SP-D mRNA in lung tissues. The ultrastructures of AT Ⅱ cells were studied with transmission electron microscopy. Results Both SP-D mRNA and SP-D levels decreased after 12 hrs of LPS administration. The SP-DmRNA level reached a nadir at 24-36 hrs, but the SP-D level was reduced to its nadir by 48 hrs after LPS administration. LPS resulted in the alterations of lamellar bodies （LBs） in size （ multilamellar forms）, density （vacuole-like deformity） and number. The alterations of ultrastructures of AT Ⅱ cells were most significant at 48 hrs. The clinical symptoms of ALI rats were most severe at 48 hrs. Conclusions The alterations of the SP-D level were timedependent in the early course of LPS-induced ALI. The lowest level of SP-D occurred at 48 hrs while severe multideformities of AT Ⅱ cells were presented. A decreased level of SP-D in the lungs in the early stage of ALI may be associated with a worse clinical outcome.
出处
《中国当代儿科杂志》
CAS
CSCD
2005年第6期483-488,共6页
Chinese Journal of Contemporary Pediatrics
