摘要目的 利用MicroCT系统对百草枯(paraquat,PQ)所致肺纤维化大鼠的影像学表现和CT值变化,分析病变区域在肺脏中的主要分布部位.方法 15只Sprague Dawley大鼠随机(随机数字法)分为对照组和百草枯染毒组.染毒组以4 mg/mL质量浓度的百草枯稀释溶液按14 mg/kg一次性腹腔注射,对照组代以等剂量生理盐水注射.分别于染毒后第3,7,14,28天利用MicroCT行大鼠活体肺组织扫描,根据扫描图像所获得资料,采用单因素方差分析(t检验)和组间比较等统计学方法,分析比较各纤维化征象的显示率差异,以及在所给测定区域(称感兴趣区ROI)的平均CT值变化情况.结果 大鼠百草枯染毒后出现不同程度的肺纤维化征像,且大部分征像出现时间优势地分布于染毒1周后,病变区域优势地分布于肺脏的中下部偏外区域;ROI的CT值变化结果表明,随着染毒时间的延长肺的密度逐渐增加,且统计分析可见肺纤维化的发生发展在左右肺上差异无统计学意义(P>0.05),但在肺脏不同的部位间纤维化程度存在的差异具有统计学意义(P<0.05或P<0.01).结论 肺纤维化时各征像出现的时间不同,优势地分布于1周后;肺组织的密度随肺纤维化发展时间的延长逐渐增加,且其病变区域主要集中于肺脏的中下叶偏外围部分.

abstractsObjective To analyze the distribution of main lesion areas in pulmonary fibrosis induced by paraquat in rats by means of radiographic imaages and varied CT value by using MicroCT. Methods A total of 15 male Sprague Dawley rats were randomly (random number) divided into control group and paraquat poisoned group. group. The rats in exposure group were treated with dilute solution of paraquat (4mg/ mL) in dose of 14mg/kg injected intraperitoneally, and the rats in control group were treated with the same volume of saline instead. The lung tissues of all rats were scanned in vivo by using MicroCT on the 3rd, 7th , 14th and 28th days after paraquat or saline administration, respectively. The data from scanned images, rates of observable signs of pulmonary fibrosis and average CT value variation in given regions (region of interest, ROI) were compared between groups and different durations after poisoning by using statistical methods as one factor analysis of variance (t-test). Results Compared with the control group, the rats with acute paraquat poisoning appeared varying degrees of the signs of pulmonary fibrosis. Most of the lesion areas predominantly spread over the lateral regions of the lower lobe of lung, and appeared mainly one week after paraquat poisoning. The opacity of lung shadow seen on the radiograph was significantly increased with time extended after exposure to PQ as a consequence of CT value variation in ROI, and there was no difference in the development of pulmonary fibrosis between right lung and left lung ( P > 0. 05), but there were differences in the extent of fibrosis at different areas in lung (P <0.05 or P < 0.01). Conclusions The signs of pulmonary fibrosis predominantly appeared one week after poisoning. The opacity of lung shadow was increasing gradually during the course of pulmonary fibrosis developed in rats in paraquat poisoning group, and lesion areas predominantly spread over the lateral regions of the lower lube of lung.