RAT AIRWAY CHANGES AFTER CHALLENGE WITH TRIMELLITIC ANHYDRIDE: EFFECT OF DIETHYLCARBAMAZINE CITRATE AND OMEGA-3 FATTY ACIDS

Abstract

Trimellitic anhydride (TMA), an acid anhydride widely used in the plastics industry, can induce occupational asthma in man. This study aims to test the effect of diethylcarbamazine citrate (DEC) and omega-3 fatty acids (ω-3 FAs) as anti-inflammatory agents against pulmonary inflammation induced by TMA challenge. Sensitized albino rats (Rattus albus) were challenged for once with TMA by intra-tracheal instillation of TMA-rat serum albumin (RSA) conjugate. DEC and ω-3 FAs (100 and 600 mg/kg) were given once/day for five days before challenge. After 24 hours of challenge, bronchoalveolar lavage (BAL), lung homogenates and sections for both light and electron microscopy were prepared. Activity of eosinophil peroxidase (EPO) and the quantity of red blood cells (RBCs) in BAL were measured. The EPO activity, nitric oxide (NO) and IL-4 assays in lung tissue homogenates were also measured. The presence of specific IgE was measured by heterologous passive cutaneous anaphylaxis (PCA) assay. Specific stain for collagen fibres was used. EPO in BAL were significantly decreased by both ω-3 FAs and DEC (p<0.01), while RBCs were decreased by ω-3 FAs (p<0.05). In lung homogenates, only DEC decreased (p<0.01) the EPO activity, but both DEC and ω-3 FAs decreased (pp<0.01, respectively) IL-4 level. In contrast, neither DEC nor ω-3 FAs did decrease NO. PCA was high in TMA group, but diminished obviously in ω-3 FAs than DEC groups. Histological and histochemical observations revealed TMA-induced changes, which were ameliorated by both DEC and ω-3 FAs. Ultrastructural observations revealed only changes in pneumocytes type II, which were partially resumed after ω-3 FAs treatment. This study indicated the usefulness of both DEC and ω-3 FAs in treatment of pulmonary inflammation.