Lung damage in experimental pleurodesis induced by silver nitrate or talc: 1-year follow-up.
OBJECTIVE
To compare the lung damage caused by intrapleural silver nitrate (SN) with that caused by talc over a 12-month period.


METHODS
One hundred forty rabbits received an intrapleural injection of 0.5% SN or 400 mg/kg talc slurry in 2 mL saline solution. Groups of 10 rabbits were killed after 1, 2, 4, 6, 8, 10, or 12 months. The macroscopic pleurodesis, microscopic lung changes (ie, collapse, hemorrhage, and edema), and cellular infiltrates (number and proportion of cells) were graded on a scale of 0 to 4.


RESULTS
The mean (+/- SEM) adhesion score after SN injection (3.3 +/- 0.1) was higher (p < 0.001) than that after talc injection (2.3 +/- 0.1). The mean alveolar collapse score was greater (p < 0.001) 1 month after SN injection (2.2 +/- 0.3) than after talc injection (0.2 +/- 0.1) and was similar from the second month on. The degree of parenchymal hemorrhage, by alveolar collapse score, (SN injection, 0.2 +/- 0.1; talc injection, 0.2 +/- 0.0) and edema (SN injection, 0.4 +/- 0.1; talc injection, 0.3 +/- 0.1) was minimal in both groups (p > 0.05). One month after the injection, the total number of inflammatory cells was greater (p < 0.001) in rabbits that had received SN injections (2.7 +/- 0.3) than in those that had received talc injections (1.2 +/- 0.1). From the second month on, cellularity decreased and became similar in both groups. The cellular profile was different, with a predominantly neutrophilic reaction after talc injection and a predominantly eosinophilic reaction after SN injection.


CONCLUSIONS
Rabbits injected with intrapleural 0.5% SN had significantly higher scores for adhesions than did those that had received talc injections, with mild and reversible alveolar collapse and an eosinophilic responses, conditions showing a clear tendency to normalize with time.
Vargas
Francisco S
FS
Pleura Laboratory, Division of Respiratory Diseases, University of São Paulo Medical School, R. Itapeva 500 cjto 4C, Bela Vista, São Paulo, Brazil CEP 01332-000. vargasfs@terra.com.br
Antonangelo
Leila
L
Capelozzi
Vera
V
Vaz
Marcelo A C
MA
Genofre
Eduardo H
EH
Marchi
Evaldo
E
Teixeira
Lisete R
LR
D000818:Animals; D004804:Eosinophils / Q000473:pathology; D007274:Injections, Intraperitoneal; D008168:Lung / Q000187:drug effects* / Q000473:pathology; D009504:Neutrophils / Q000473:pathology; D018700:Pleurodesis; D011650:Pulmonary Alveoli / Q000473:pathology; D011817:Rabbits; D012835:Silver Nitrate / Q000008:administration & dosage / Q000009:adverse effects*; D013627:Talc / Q000008:administration & dosage / Q000009:adverse effects*
D013627:Talc; D012835:Silver Nitrate