Intrapleural low-dose silver nitrate elicits more pleural inflammation and less systemic inflammation than low-dose talc.
OBJECTIVE
Several systemic effects have been described after talc pleurodesis. The aim of this study was to assess the systemic response induced by low, nonpleurodesis-inducing doses of talc and silver nitrate in an experimental model in rabbits.


METHODS
Groups of six rabbits were injected intrapleurally with talc, 100 mg/kg or 400 mg/kg, and silver nitrate, 0.1% or 0.5%. After 6, 24, or 48 h, samples of blood and pleural fluid were collected and assayed for leukocytes, percentage of neutrophils, lactate dehydrogenase, interleukin-8, and vascular endothelial growth factor (VEGF) levels. Preinjection blood samples were used as normal blood controls.


RESULTS
Silver nitrate 0.1% induced a more intense pleural inflammation than that produced by talc 100 mg/kg. In contrast, talc 100 mg/kg induced a more pronounced acute systemic response with higher values of WBCs and neutrophils, whereas silver nitrate 0.1% produced no significant increases in leukocytes or neutrophils. The serum interleukin-8 and VEGF levels increased in all groups, and decreased with time only in the silver nitrate 0.1% group. The highest serum VEGF levels were observed in the talc 100 mg/kg group.


CONCLUSIONS
In conclusion, 0.1% silver nitrate produced an intense pleural inflammatory response with a less evident systemic response in comparison to 0.5% silver nitrate and talc 100 mg/kg or 400 mg/kg.
Marchi
Evaldo
E
Pleura Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo Medical School, Brazil, Rua Lucia B. Passarin, 590, Ap.42, Jundiai, São Paulo, Brazil. evmarchi@uol.com.br
Vargas
Francisco S
FS
Teixeira
Lisete R
LR
Acencio
Milena M P
MM
Antonangelo
Leila
L
Light
Richard W
RW
D000818:Animals; D002424:Caustics / Q000008:administration & dosage*; D007249:Inflammation / Q000139:chemically induced*; D007263:Infusions, Parenteral; D007509:Irritants / Q000008:administration & dosage; D008297:Male; D010994:Pleura / Q000187:drug effects* / Q000276:immunology; D010996:Pleural Effusion / Q000139:chemically induced / Q000276:immunology; D018700:Pleurodesis / Q000379:methods*; D011817:Rabbits; D012835:Silver Nitrate / Q000008:administration & dosage*; D013627:Talc / Q000008:administration & dosage
D002424:Caustics; D007509:Irritants; D013627:Talc; D012835:Silver Nitrate