Melatonin: is it an effective antioxidant for pulmonary contusion?

BACKGROUND: The goal of the present study was to evaluate the antioxidant effects of melatonin on pulmonary contusion (PC) caused by isolated blunt thoracic trauma (BTT) in an experimental rat model. MATERIALS AND METHODS: A total of 49 rats were divided into three groups: control group (CG), trauma group (TG), and melatonin group (MG). PC was induced by isolated BTT for all the groups except the control group. Intraperitoneal melatonin was administered to the MG after trauma. Blood and tissue samples were collected from the groups. Malondialdehyde (MDA), total oxidant capacity and total antioxidant capacity (TAOC), arterial blood gas, and other biochemical parameters such as urea, creatinine, alanine aminotransferase (ALT), and aspartate aminotransferase were measured. Lung tissue samples were collected for histopathology. RESULTS: On day 2, blood MDA and total oxidant capacity levels were lower, and TAOC levels were higher in the MG compared with the TG (P < 0.001). Blood pH, PO2, and PCO2 of the MG significantly improved on day 2 compared with the TG (P ≤ 0.001). Compared with the TG, histologic damage scores of the MG decreased on day 2 (P = 0.013). Urea, creatinine, ALT, and aspartate aminotransferase levels of the MG on day 2 were lower than TG parameters (P = 0.01, P = 0.02, P = 0.05, and P < 0.001, respectively). CONCLUSIONS: Our findings demonstrate that melatonin can improve the histopathology of PC and distant organs such as liver and kidney by diminishing oxidative stress. All these findings suggest that melatonin may be an effective new therapeutic agent for PC caused by BTT.

Investigation of protective role of curcumin against paclitaxel-induced inner ear damage in rats.

OBJECTIVES/HYPOTHESIS: The aim of this study was to investigate the potential protective effect of curcumin on paclitaxel-induced ototoxicity in rats by means of immunohistochemical and histopathological analysis and distortion product otoacoustic emissions (DPOAEs). STUDY DESIGN: Animal study. METHODS: Forty Sprague-Dawley rats were randomized into five groups. Group 1 was administered no paclitaxel and curcumin during the study. Groups 2, 3, 4 and 5 were administered 5 mg/kg paclitaxel; 200 mg/kg curcumin; 5 mg/kg paclitaxel, followed by 200 mg/kg curcumin; 200 mg/kg curcumin and a day later 5 mg/kg paclitaxel followed intraperitoneally by 200 mg/kg curcumin once a week for 4 consecutive weeks, respectively. After the final DPOAEs test, the animals were sacrificed and their cochlea were prepared for hematoxylin and eosin and caspase-3 staining. RESULTS: The DPOAEs thresholds and histopathological and immunohistochemical findings were substantially correlated in all groups. The histopathologic findings in the cochlea of the paclitaxel-treated animals showed not only changes in the organ of Corti, but also damage to the stria vascularis and spiral limbus, including nuclear degeneration, cytoplasmic vacuolization, and atrophy of intermediate cells. Additionally, cochlear changes in group 2, such as intense apoptosis, were confirmed by caspase-3 immunohistochemical staining. In group 4, coreceiving curcumin could not sufficiently prevent paclitaxel-induced ototoxicity, and the results in group 5 were similar to the control group. CONCLUSIONS: In our study, we have concluded that pre- and coreceiving curcumin can significantly protect the cochlear morphology and functions on paclitaxel-induced ototoxicity in rats. Curcumin might be considered as a potential natural product that, used as a dietary supplement, could be easily given to patients undergoing paclitaxel chemotherapy. LEVEL OF EVIDENCE: NA