ABSTRACT
Cement dust is an atmospheric pollutant which poses a significant threat to the environment and humans. This study investigated the histological changes in the lungs and respiratory tract and some haematological and biochemical changes in Wistar rats following exposure to cement dust. Twenty-four adult Wistar rats weighing between 250 g and 280 g were randomly assigned into 4 groups; (Group A-D) comprising of 6 rats per group. Group A rats were placed in a cement dust free chamber while Group B - D rats were exposed to various concentrations of cement dust dispersed from 5 g, 10 g and 20 g of cement respectively. Duration of exposure to cement dust was 30 consecutive days over a period of 1 hour daily via a Dust-Distributor Glass Chamber (DDGC). The weights of the rats were taken after 30 days and the difference between them and previous weights were noted. At the end of the 30th day exposure, the animals were sacrificed under chloroform anesthesia and the larynx, trachea, bronchi and L lungs were excised and processed for histological examination. Blood samples were collected for haematological and biochemical analysis. Statistical Package for Social Sciences version 20 was used in analyzing data. The data was subjected to statistical analysis and P value calculated using the students’ttest. The results were presented as mean and standard error of mean. P < 0.05 was considered significant. Findings of the study for body weight showed that cement dust caused significant decrease in body weights of the exposed rats across all the groups and also caused some derangements in biochemical parameters, especially manganese, bicarbonate, urea and creatinine which may result ultimately in manganese poisoning, respiratory problems and renal failure. Cement dust similarly decreased some haematological parameters such as lymphocytes and basophils, haemoglobin and haematocrit, red blood cells and other red cell indices with associated reticulocytosis. These deranged haematological parameters may lead to anaemia and increased susceptibility to infections. Moreover, cement dust caused mucosal inflammation in the larynx, trachea, bronchi and bronchioles, mucosal ulceration, vascular ulceration as well as haemorrhages in the tracheal and bronchial tracts, inflammation of the lung interstitial space, activation of bronchial and bronchiolo-alveolar lymphoid aggregates and patchy alveolar collapse. The injuries are consistent with usual histological findings in laryngitis, tracheitis, bronchitis, bronchiolitis and pneumonia. In all, cement dust caused biochemical, haematological and histomorphological derangements which are capable of compromising respiratory and haematological function and could ultimately lead to mortality.
