Investigation of the protective effect of micromeria congesta essential oil on LPS-induced acute lung injury in rats

Micromeria congesta plant is used for respiratory tract disorders especially in Şanlıurfa, Adıyaman and Gaziantep provinces. In our study, the protective effect of the essential oil of M. congesta plant, which has not been studied much, against lung damage induced by septicemia in rats was investigated. M. congesta plant was collected from the mountains in Açıkyazı and Dağeteği neighborhoods. Essential oil was extracted in Clevenger device. The content analysis of the essential oil was performed by GC-MS. The 36 Wistar albino rats used in the study were divided into six groups. The first group received M. congesta essential oil 12.5 mg/kg, the second group 25 mg/kg, the third group 50 mg/kg once a day for seven days by gavage. Dexamethasone 5 mg/kg was administered intraperitoneally to the fourth group only on the 7th day. The fifth group received only LPS and the sixth group was designated as the control group. The first five groups were administered LPS 5 mg/kg intravenously at the end of the seventh day to induce septicemia. The rats were bled 6 hours after LPS administration and sacrificed by removing the lungs under anesthesia. TAS, TOS, OSI, Glucose, Urea, Creatine, Crp, ALT, AST, HDL, LDL parameters were analyzed in blood serum. NLRP3, Caspase-3 ve TNF-𝛼 gene expressions were analyzed in molecular analysis of lung tissue. At the end of the study, 28 components were detected in the content analysis of the essential oil with GC-MS device. Among these 28 components, Piperitenone Oxide was detected at the highest rate, followed by Pulegone, N-Hexadecanoic acid, Piperitenone, Spathulenol, Carvone Oxide and Isomenthone at increasing rates, respectively. As a result of biochemical analysis, it was determined that blood glucose value was low depending on the dose of M. congesta essential oil. It was observed that M. congesta essential oil reduced the toxic effect of LPS on the kidneys at low doses and decreased the blood urea value. In the examination of lung tissues at the molecular level, it was determined that the essential oil of M. congesta plant exhibited a strong anti-inflammatory effect by positively affecting the expressions of NLRP3, Caspase-3 and TNF-α genes and by significantly suppressing the inflammatory pathways. Again, the anti-inflammatory effect of the essential oil of M. congesta plant was examined by histopathological methods and it was observed that histopathological findings were alleviated depending on the dose. As a result, it was determined by biochemical, molecular and histopathological observations that the essential oil of M. congesta plant has an anti-inflammatory effect.