Chemical pleurodesis is frequently employed to obliterate the pleural space most commonly for the treatment of neoplasia. Talc (TL) and Silver Nitrate (SN) induce pleurodesis by directly injuring the pleura. The injury results in intense inflammation with secondary collagen and elastic deposition.The aim of this study was to evaluate comparatively the extracellular matrix collagen and elastin profiles in the experimental pleurodesis induced by talc or silver nitrate.
420 rabbits divided in 2 groups received in a volume of 2mL, TL 400mg/kg or 0.5% SN. Ten animals of each group were sacrificed in the following times: 15 and 30 minutes; 1, 2, 4, 6 and 12 hours/ 1, 2, 3, 5, 7, 15 and 21 days and 1, 2, 4, 6, 8, 10 and 12 months. For the collagen evaluation pleural samples were stained by the picrosirius-polarization method. Elastic component was evaluated by histochemical staining for elastin. The quantitation of these parameters was done in an image analyzer system. The measurements were expressed in mm2 corrected for 1000mm2 of analyzed pleura. The student t test (for parametric data) and Man-Whitney rank sun test (for non-parametric data) were used to compare the values between groups. A p value of <0.05 was considered significant.
We observed an increased total collagen deposition with time for both groups more pronounced for the SN group. (Graph 1). Elastin became more pronounced after day 21 for both groups with a peak around 1–2 months. On the 10 month, talc group have demonstrated a higher elastin expression than SN group (Graph 2).
CONCLUSION AND CLINICAL IMPLICATIONS: Total collagen deposition increased with time for both groups, with a tendency for higher values in SN group when compared to talc group (significant for 2 days and 10 months). Elastin presented a peak of deposition around 1–2 months in both groups with the higher values occurring in talc group. In some slides of talc group persistent pleural granuloma were observed.
L. Antonangelo, None.