Pulmonary Alveolar Macrophages (PAMs) are the initial phagocytic cells that encounter foreign material and particulates deposited in the terminal airways. The study of PAMs had been facilitated by its availability in Bronchoalveolar lavage (BAL) fluid by evaluation. Seventy healthy adult male (Rattus rattus norvegicus albinus), twenty–five weeks old. For each rat, the BAL was performed by tracheal cannulation and a total volume of 48ml phosphate-buffered saline (PBS; pH 7.4, 37°C) was installed in 8ml aliquots for 20 sec
Different stains were used for cytological study including: PAMs morphology, PAMs count (without staining), differential BAL cells count and morphometry of PAMs by (Global Lab Image /2) software was used in this study. Cytochemical study of PAMs was done by the identification of esteratic activity which was demonstrated against the substrate α-naphthyl acetate (ANAE), the simultaneous azo-coupling method. Microspetro–photometry was used for studying the quantization of PAMs esterase cytochemistry. In BAL procedure, 92% of total lavage fluid was recovered. Stained BAL smears showed that the examined PAMs were mostly mononucleotides; the nuclei of these cells were variable in shape. The mean of total cells were counted from recovered lavage fluid was 2.6×106 cell /animal. The percentages of differential BAL cells count were composed of 85-90% PAMs, 5-6% lymphocytes, 3-4% granulocytes and 3-4% epithelial cells. The diameter of PAMs was identified which ranged between (14-35μ). The mean of PAMs area was 57μ2±1.03 and the mean of nucleus area was 17.6μ2±1.3. The ratio of nucleus areas to cytoplasm area was1:2. The Final Reaction Product of the ANAE enzymatic reaction was homogenous brown reddish color. It was homogenous in distribution although the distribution was regular within the area of cytoplasm and nucleus of PAMs while other BAL cells showed negative reaction. 95% of total PAMs were positive in reaction. The mean of optical density of final reaction product of esteratic activity in PAMs was 1.782±0.004.