Cyclophosphamide (CYP) is an anticancer agent widely used in chemotherapy. It has been suggested that CYP causes toxicity in many organs, including the lungs and testes. Many studies have indicated that some antioxidants have possible protective effects against CYP’s side effects. This study aimed to investigate the protective effect of quercetin (QUE) on CYP-induced lung toxicity in rats using histologic and biochemical methods.

In the study, 50 male Sprague-Dawley rats weighing 220–250g were used. There were 4 experimental groups and 1 control group. Group I is the control group, which was given only intragastric (i.g.) solvent (corn oil) for 7days. Group II was given i.g. corn oil for 7days as a placebo, and a single dose of intraperitoneal (i.p.) CYP (200mg/kg) was given on day 7. Groups III and IV, respectively, were given QUE in doses of 50 and 100mg/kg, dissolved in corn oil, and administered i.g. for 7days. In addition, a single dose of CYP (200mg/kg, i.p.) was administered on the 7th day of study. In Group V, a 100mg/kg dose of QUE was given to rats i.g. for 7days. On the 8th day of the experiment, all groups of rats’ blood and lung tissue samples were collected for analysis of oxidative stress parameters and histopathological examinations.

In the biochemical result (although oxidative parameters were increased in favor of tissue damage) QUE administration revealed attenuated CYP toxicity in the rats ‘lungs. In histologic analysis, QUE prevented the CYP-mediated tissue damage and the increase in mast-cell densities in the rats’ lung tissues.

The results of the present study have revealed that QUE provides a possible protective effect by inhibiting ROS and mast cell degranulation in induced lung damage.