Stereological estimation of the volume weighted mean volumes of alveoli and acinar pathways in the rat lung to characterise alterations after ischaemia/reperfusion

Abstract

The aim of this study was to characterise pulmonary reimplantation injury in isolated, perfused rat lungs following 2 h of cold ischaemia, and 50 min. of in vitro reperfusion. The effects of 2 differently composed lung preservation solutions (low potassium Euro‐Collins and Celsior; each n=5) were examined in comparison with untreated, nonischaemic control lungs (n=3). After fixation by vascular perfusion and tissue collection by systematic random sampling, the volume weighted mean volume (v) of alveoli and acinar pathways was estimated by light microscopic stereology using the method of point sampled intercepts in plastic embedded, Azan‐stained material. Significantly higher v of alveoli and acinar paths was found in the Celsior group than in Euro‐Collins preserved lungs. However, in the controls the size of acinar pathways was similar to Celsior preserved lungs whereas alveolar size was comparable to preservation with Euro‐Collins. The between‐animal coefficient of variation of alveoli was very low in controls and Celsior preserved but higher in the Euro‐Collins group. Size distribution of alveoli and acinar paths in 15 size classes was largely homogeneous in all groups tested. In the Euro‐Collins group the fractions of both class 1‐alveoli and class 1‐acinar paths significantly exceeded those of the other groups. Widely expanded alveoli (size classes 13–15) only occurred after preservation with Celsior whereas wider acinar paths (size class 15) were found in the Celsior group and in the controls. It is concluded that lung preservation with low‐potassium Euro‐Collins and Celsior solutions may act differently on distinct spaces in the distal gas‐exchange regions of lungs. This may be due to selective effects on pulmonary surfactant activity and on elastic tissue elements in the alveolar ducts, respectively. Additionally, the method of point sampled intercepts is considered to be an efficient tool to evaluate the effects of different preservation solutions on lung parenchyma.

Lung endothelial monocyte-activating protein 2 is a mediator of cigarette smoke–induced emphysema in mice

“…These effects were recapitulated in vivo, where direct lung delivery via aerosol nebulization of recombinant mature EMAPII protein 3 times weekly for 2 weeks (5 μg/ml) activated caspase-3 in lung lysates ( Figure 3D). This effect was dose dependent and was associated with airspace simplification after 4 weeks of administration (Supplemental Figure 4), measured as a decrease in surface-to-volume ratio by stereological morphometry, indicative of emphysema development (31,32). The EMAPII-induced caspase activation was inhibited by concomitant application of a general caspase inhibitor quinoline-ValAsp-difluorophenoxymethylketone (Q-VD-OPH) ( Figure 3D), a new generation inhibitor with reduced toxicity and increased specificity in comparison with other halogenated methylketone-based caspase inhibitors (33).…”

“…Tuder for MetaMorph (49). In addition, the point-sampled intercept method was used to determine the volume-weighted mean acinar airspace volume (31). Measurements were performed on coded, Richardson-stained sections of systematic, uniform, and random samples of lungs embedded into glycolmethacrylate.…”

Biodistribution and Efficacy of Targeted Pulmonary Delivery of a Protein Kinase C-δ Inhibitory Peptide: Impact on Indirect Lung Injury

“…Under continued anesthesia and mechanical ventilation, the thorax was opened and the lungs were fixed by vascular perfusion according to standard protocols (Fehrenbach et al, 1999) or by gravity fixation intratracheally as previously described (Mondrinos et al, 2014). Lung tissue samples were obtained from different locations in the left and right lung to assess the uniformity of delivered peptide distribution.…”

Sequential targeted deficiency of SP-A and -D leads to progressive alveolar lipoproteinosis and emphysema

“…As a measure for air space size, the mean linear intercept length and volume-weighted mean volume ( v) of terminal air spaces were determined. The v of terminal air spaces was estimated by the point-sampled intercepts method (10), which has been applied successfully to lung alveoli previously (9,23). Linear intercept length and v measurements were done from "wall to wall," thereby including alveoli and alveolar ducts (9).…”