title: Low concentration silver nitrate pleurodesis in rabbits: optimal concentration for rapid and complete sclerosing effect.
abstract: Pleurodesis is a useful therapeutic tool when local treatment of a recurrent malignant pleural effusion or pneumothorax is needed. We have previously demonstrated that the intrapleural injection of 0.5% silver nitrate (SN) produces a significant pleurodesis, while 0.25% SN has no sclerosing effect in a rabbit model. The objective of this study was to determine the minimum concentration of SN needed to induce pleurodesis in our experimental model. One hundred twenty male New Zealand white rabbits received 0.3, 0.4, or 0.5% SN (40 animals per group) in a total volume of 2 mL instilled intrapleurally. These animals were sacrificed 3, 7, 14 or 28 days after the intrapleural injection (n = 10 animals per group), and the pleural spaces were then assessed grossly for evidence of pleurodesis and microscopically for evidence of fibrosis and inflammation. By 28 days, all concentrations of SN had produced a pleurodesis. There was evidence of a gross pleurodesis 7 days post-injection in animals that received 0.5% SN (score of 2.8 +/- 0.2 on a scale of 0-4). After 14 days, significant pleural adhesions were evident in the groups that received 0.4 or 0.5% SN. We conclude that SN concentrations as low as 0.3% can effectively produce a pleurodesis within 28 days of intrapleural injection. However, the precocious pleurodesis development observed 7 days after the intrapleural injection of 0.5% SN suggests that this concentration may be optimal when a fast result is necessary.
authors.affiliation: Laboratory of Pleura--Pulmonary Division, Heart Institute (InCor), University of Sao Paulo Medical School, Brazil. pnelisete@incor.usp.br
authors.forename: L R
authors.initials: LR
authors.lastname: Teixeira
authors.forename: F S
authors.initials: FS
authors.lastname: Vargas
authors.forename: L
authors.initials: L
authors.lastname: Antonangelo
authors.forename: V C
authors.initials: VC
authors.lastname: Mattos
authors.forename: M A C
authors.initials: MA
authors.lastname: Vaz
authors.forename: M M P
authors.initials: MM
authors.lastname: Acencio
authors.forename: E
authors.initials: E
authors.lastname: Marchi
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005355:Fibrosis / Q000139:chemically induced / Q000378:metabolism; D007273:Injections, Intramuscular; D008297:Male; D010994:Pleura / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D018700:Pleurodesis; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D011817:Rabbits; D012597:Sclerosing Solutions / Q000008:administration & dosage; D012720:Severity of Illness Index; D012835:Silver Nitrate / Q000008:administration & dosage*; D013997:Time Factors
chemical_list: D012597:Sclerosing Solutions; D012835:Silver Nitrate