视黄酸对放射性肺损伤大鼠肺组织CD36表达的影响

目的探讨视黄酸对放射性肺损伤肺组织病理改变和信号蛋白CD36表达的影响。方法将80只健康雄性Wistar大鼠随机分为4组：正常对照组（A组）、单纯给药组（B组）、单纯照射组（C组）和照射加给药组（D组）,每组20只。C、D两组大鼠行6MV-X线15 Gy全胸野照射,B、D两组大鼠给予20 mg/（kg.d）视黄酸制剂灌服。于照射后第1、2、4、8周行支气管肺泡灌洗,计数肺泡灌洗液细胞数,留取肺组织标本,作HE和Masson染色、免疫组织化学法检测CD36表达。结果 HE和Masson染色提示照射后的1周始肺泡腔有炎性细胞渗出,继之间质水肿,4及8周出现肺泡腔变小结构破坏,局部实变,肺间质出现胶原纤维;B组与A组比较各时间段的病理无明显差别,但D组与C组比较大鼠肺炎和肺水肿减轻,肺组织胶原纤维量减少。肺泡灌洗液的细胞总数C组与A组比较各时间段都明显增高（P〈0.01）,D组与C组比较,肺泡灌洗液总数降低,第4、8周差别有统计学意义（P〈0.005）。免疫组织化学检测示：A组与B组检测的4个时间点CD36表达差别均无统计学意义;C组和D组与A组比较在放疗后的第1、2、4、8周时间段CD36表达均明显增强（P〈0.0001）,以C组增强更明显;D组与C组比较CD36表达减弱,以第4、8周表达减弱更明显。结论放射性肺损伤时肺组织CD36表达明显增强,视黄酸对大鼠正常肺组织的CD36表达无影响,但它能从蛋白质水平有效抑制放射诱导的CD36表达,对放射性肺损伤有防治作用,为临床上用其治疗放射性肺损伤提供了实验依据。

Effect of retinoic acid on expression of CD36 in lung tissue of rats with radiation-induced lung injury

Objective To investigate the effect of retinoic acid（RA） on the expression of CD36 in lung tissue of rats with radiation-induced lung injury. Methods Eighty Wistar rats were randomly divided into four groups,with 20 rats in each group,including control group（A）,RA treatment group（B）,radiation group（C）,and radiation with RA treatment group（D）.Rats in groups C and D were radiated with 6 MV-X ray of linear accelerator at a dose of 15 Gy,rats in groups B and D were given with 20 mg/（kg·d） RA by gastrogavage.One,2,4 and 8 week after radiation samples of bronchoalveolar lavage fluids（BALF） and lung tissue were taken for HE stain,Massion stain and immunohistochemistry stain to detect the expression of CD36. Results HE and Massion staining showed inflammatory cells exudation in the alveolar spaces 1 week after radiation,followed by interstitial edema and destroyed structure and collagen fibers appearing in pulmonary interstitial at 4 and 8 week.No significant difference of pathology was seen between group A and B at all time points,while the rat pulmonary inflammation and edema alleviated,with decreased collagen fibers in group D compared to group C.The number of cells in BALF increased significantly in group C compared to group A at all time points（P0.01）,while decreased in group D compared to group C especially at week 4 and 8（P0.005）.There was no difference in CD36 expression between group A and B at all time points,while it was enhanced significantly in group C and group D at week 1,2,4 and 8 compared to group A（P0.0001）.The expression of CD36 was weakened in group D compared to group C,especially at week 4 and 8. Conclusion The expression of CD36 is increased significantly in lung tissue of rats with radiation-induced lung injury,and retinoic acid can inhibit CD36 expression,which suggests RA might be used to prevention and treatment of radiation-induced lung injury.