染色质浓缩对细胞核DNA含量检测的影响

目的利用三种不同方法制备小鼠肝细胞涂片，探讨染色质浓缩对图像分析仪测量DNA含量的影响。方法本文选取10只成年健康雄性小鼠，采用传统涂片、液基制片法和甲醛固定后液基制片法制备小鼠肝细胞涂片。Feulgen染色。TIGER细胞图像分析仪分别测量三种涂片内肝细胞核的积分光密度、平均光密度和面积。结果三种涂片内肝细胞核分布均匀，轮廓清晰，呈紫红色。与传统涂片法相比。液基法内肝细胞核面积明显减小。类色质高度浓缩；相同倍体的肝细胞核在传统涂片中面积最大，平均光密度最低，各倍体间的比值最接近2和4，积分光密度CV值最低（〈3．5）。固定法和液基法平均光密度明显升高，各倍体间比值明显偏离2和4。积分光密度CV值〉6。结论不同制片方法可导致同一类型、处于相同功能状态的细胞核染色质浓缩程度产生明显差异，染色质浓缩可导致平均光密度值升高，积分光密度值降低，测量结果的精确性和准确性降低。

Influence of chromatin condensation on measurement of nuclear DNA content

Purposes To investigate the influence of nuclear chromatin condensation on measurement of DNA content.Methods Smears of liver cells from ten rats were prepared by conventional preparation,liquid-based preparation and liquid-based preparation with Feulgen staining,taking samples from liver tissue fixed in 4% buffered formaldehyde.A TIGER image analysis system was used to measure IOD,AOD AND A value of the nuclei.Results The amaranthine nuclei had a distinct outline and distributed evenly on the slide.The area of nuclei in liquid-based preparation was much smaller and chromatin was more condensed in comparison with those in conventional smear.The nuclei in conventional smears had the largest value of area and the value of AOD,and CV of IOD,the IOD ratio among diploid,tetraploid and octaploid DNA was most close to 2 and 4,and the CV of IOD exceeded 6%.Conclusion The same specimen may have different degree of chromatin condensation caused by different preparation procedures.Chromatin condensation can increase AOD and decrease IOD value,and finally the accuracy and precision of ICM will be decreased.