Related Experiment Video
Updated: Mar 27, 2026
Efficient Method for Imaging Murine Lungs that Preserves Spatial Dynamics of Fungal Spores in the Airways
Published on: December 13, 2024
Small molecule distribution in rat lung: a comparison of various cryoprotectants as inflation media and their
Sooraj Baijnath1, Adeola Shobo1, Linda A Bester2
1Catalysis and Peptide Research Unit, University of KwaZulu-Natal, Westville Campus, E-Block, 6th Floor, Room E1-06-016, Durban, South Africa.
Abstract:
Given the recent explosion of mass spectrometric imaging (MSI), it has become easier to assess drug tissue localisation without the use of radiolabeling and other more complex methods (such as PET and MRI). For MSI tissue preparation is of utmost importance, however, the lung in particular does pose some difficulties with imaging since it is made up of a number of air-filled alveoli. These organs are known to collapse when the thoracic cavity is pierced, losing its structural integrity and giving poor histological representation for drug distribution analysis. The use of cryoprotectants as a tissue inflation media will aid in the preservation of the lung's structural integrity during MSI experiments involving small molecule distribution. Various established cryoprotectants (DMSO, PvP, ethylene glycol, sucrose, DMEM, control serum, OCT) were selected as lung inflation media for MSI analysis of gatifloxacin (GAT). Female Sprague-Dawley rats were treated with GAT (10 mg/kg b.w) via i.p. injection. After 15 min the animals were terminated by halothane overdose, and each set of tissue inflated with a specific agent. Cryosections were made and MSI conducted to determine drug tissue distribution. During the early stages of the experimental procedure some crypreservatives were eliminated due to difficulties with sample preparation. While others displayed excellent preservation of the tissue structure and integrity. Following MSI analysis, some agents showed homogenous drug distribution while some displayed heterogeneous distribution favoring the basal periphery. Taking into account the physiology of the lung and previous MRI investigations of its perfusion, it is expected that a systemically administered drug would localize in the basal areas. DMSO and DMEM proved to display this distribution pattern while keeping structural integrity intact. However, the later was ruled out since it showed complete suppression of GAT in solution. From the cryoprotectants selected for this study, DMSO is the most promising lung inflation media focusing on small molecule distribution via MSI.
Insights
Dimethyl sulfoxide (DMSO) effectively preserves lung tissue integrity for mass spectrometric imaging (MSI) of drug distribution. This cryoprotectant is ideal for studying small molecule localization in lung tissue, overcoming common imaging challenges.
Area of Science:
- Pharmacology
- Analytical Chemistry
- Biomedical Imaging
Background:
- Mass spectrometric imaging (MSI) offers a powerful tool for drug tissue localization.
- Lung tissue presents unique challenges for MSI due to its air-filled structure and susceptibility to collapse.
- Preserving lung structural integrity is crucial for accurate drug distribution analysis.
Purpose of the Study:
- To evaluate various cryoprotectants as lung inflation media for MSI.
- To assess the impact of different inflation media on lung tissue integrity and drug distribution.
- To identify the optimal cryoprotectant for small molecule distribution studies in lung tissue using MSI.
Main Methods:
- Selected cryoprotectants (DMSO, PvP, ethylene glycol, sucrose, DMEM, control serum, OCT) were tested as lung inflation media.
- Gatifloxacin (GAT) was administered to Sprague-Dawley rats, followed by lung tissue collection.
- Cryosections were prepared and analyzed using MSI to determine GAT distribution.
- Tissue structural integrity was assessed after inflation with different agents.
Main Results:
- Dimethyl sulfoxide (DMSO) and DMEM maintained lung structural integrity.
- DMSO and DMEM showed drug distribution favoring basal lung areas, consistent with physiological expectations.
- DMEM suppressed GAT in solution, making it unsuitable for analysis.
- DMSO demonstrated promising results for preserving tissue and showing drug distribution patterns.
Conclusions:
- Dimethyl sulfoxide (DMSO) is the most promising cryoprotectant for lung inflation in MSI studies of small molecule distribution.
- Effective lung inflation media are essential for overcoming MSI challenges in pulmonary drug distribution analysis.
- This study highlights DMSO's utility in maintaining lung architecture for accurate drug localization.
