Histological comparison of rats lung treated with chloroquine
1 Department of Biology, College of Science, Tikrit University, Iraq.
2 Department of Medical Biotechnology, College of Science, Tikrit University, Iraq
3 Department of Anatomy and Histology, College of Medicine Tikrit University, Iraq.
Research Article
International Journal of Life Science Research Archive, 2026, 10(02), 159-166.
Article DOI: 10.53771/ijlsra.2026.10.2.0049
Publication history:
Received on 14 May 2026; revised on 21 June 2026; accepted on 24 June 2026
Abstract:
Chloroquine is an antimalarial drug with immunomodulatory and anti-inflammatory properties commonly used to treat certain autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. The drug functions by disrupting cellular processes and restricting the replication and activity of intracellular parasites. This study aims to evaluate the dose- and duration-dependent effects of chloroquine on the lung tissue of female Sprague-Dawley rats. Histological changes were compared between the treated and control groups to determine the relationship between dosage, exposure duration, and the severity of potential pathological variations. This study included 35 female Sprague-Dawley rats, divided into 7 groups of 5 animals each. The first group served as the control and received a standard diet and water throughout the experiment. The six experimental groups were administered chloroquine at varying concentrations and durations: groups 2 and 3 received 1.6 mg/kg for 35 and 50 days, respectively; groups 4 and 5 received 2.5 mg/kg for 35 and 50 days, respectively; and groups 6 and 7 received 3.8 mg/kg for 35 and 50 days, respectively. The animals were then sacrificed, and their lungs were excised for histological examination.
Histological findings in the lungs of rats treated with chloroquine revealed marked pathological changes, including widespread congestion, interstitial hemorrhage, and intravascular hemolysis. Inflammatory lymphocytic infiltration of varying degrees was also observed, along with degeneration, necrosis, and sloughing of the alveolar epithelium. Correlating with the increase in dose and duration of exposure, the severity of pathological changes increased to include thickening of bronchiolar, alveolar sacs, and air sacs walls, focal fibrosis, as well as dilation and congestion of blood vessels. Furthermore, signs of chronic inflammation emerged, characterized by dense cellular infiltration and the presence of alveolar macrophages within the lung tissue. In conclusion, these findings demonstrate that chloroquine induces dose- and duration-dependent pulmonary toxicity, characterized by progressive structural and inflammatory changes in lung tissue.
Keywords:
Chloroquine; Rat lung; Pulmonary toxicity; Pneumotoxicity
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