Modified RNA Extraction Methods to Eliminate Agarose Impurities in Precision-Cut Lung Slices

Precision-cut lung slices (PCLS) have emerged as a powerful tool for studying the biology of viable human lung tissue. However, the presence of agarose impurities compromises RNA yield and integrity during the extraction process. We tested whether using an alternative Plant kit RNA extraction method to wash agarose impurities or pre-dissolving agarose from PCLS implementing a dissolving buffer for routine RNA isolation in gel-electrophoresis would improve RNA quantity, quality, and integrity. Our results show that RNA quantity and integrity are highly compromised when using a conventional method of RNA extraction. The plant kit and dissolution of agarose increased the RNA quantity to 0.42{+/-}0.11 and 0.65{+/-}0.17 {micro}g/PCLS (measured by the Qubit) and integrity number to 6.60{+/-}0.59 and 9.13{+/-}0.39 (measured by the Bioanalyzer), respectively. The presence of impurities in conventional and Plant kit extractions misled to an overestimation of the RNA quantity and quality using the NanoDrop. The Plant kit and agarose dissolution showed a significant transcript integrity increase in GUSB (p<0.0001) and COL1A1 (p<0.05) expression, validating these methods over conventional extraction. We encourage laboratories applying PCLS experimentation to implement alternative methods to remove agarose impurities during RNA extraction, as well as to rely on sensitive quantitative techniques, such as the Qubit and Bioanalyzer, for RNA quantification and integrity measurements.