Gokhale J A, Khan S R
Department of Pathology, College of Medicine, University of Florida, Gainesville 32610.
Scanning Microsc. 1992 Jun;6(2):511-8; discussion 518-9.
In contrast to fixation of tissue in externally heated fixative, microwave-irradiation can generate uniform internal heat, which is of utmost importance for successful fixation of biological tissue. To evaluate the effectiveness of microwave-accelerated chemical fixation, we compared the structure of rat kidney fixed by a conventional method and a microwave-accelerated method, by scanning and transmission electron microscopy. Following perfusion, rat kidney pieces 1-2 mm in size were irradiated in Karnovsky's fixative in a domestic Amana microwave oven, till the temperature of the fixative reached 45-50 degrees C. For conventional fixation, tissue pieces were fixed overnight at room temperature in the same fixative. Both types of samples were processed further for electron microscopy using identical protocols. The microwave fixed samples showed excellent preservation of structure comparable to the samples fixed by the conventional method. Glomeruli and the renal tubules showed normal morphology with no cellular swelling. The cytoplasm and nuclear matrix of the epithelial cells was uniformly dense. Other fixation sensitive organelles like mitochondria and Golgi apparatus showed superior preservation with continuous membranes. These results demonstrate that microwave accelerated chemical fixation results in excellent preservation of tissue structure, reduces processing time significantly and is therefore a practical alternative to conventional protocols.
与在外部加热的固定剂中固定组织不同，微波辐射能够产生均匀的内热，这对于生物组织的成功固定至关重要。为了评估微波加速化学固定的效果，我们通过扫描电子显微镜和透射电子显微镜，比较了用传统方法和微波加速方法固定的大鼠肾脏的结构。灌注后，将大小为1 - 2毫米的大鼠肾脏组织块置于家用阿曼纳微波炉中的卡诺夫斯基固定剂中进行辐照，直至固定剂温度达到45 - 50摄氏度。对于传统固定，组织块在室温下于相同固定剂中固定过夜。两种类型的样品均使用相同的方案进一步处理以进行电子显微镜观察。微波固定的样品显示出与传统方法固定的样品相当的出色结构保存效果。肾小球和肾小管形态正常，无细胞肿胀。上皮细胞的细胞质和核基质均匀致密。其他对固定敏感的细胞器，如线粒体和高尔基体，显示出具有连续膜的更好保存效果。这些结果表明，微波加速化学固定能出色地保存组织结构，显著减少处理时间，因此是传统方案的一种实用替代方法。
