Investigation of the effects of different thyme extracts and thyme honey on chronic obstructive pulmonary disease in rats

The objective of this study is to investigate the effects of Origanum onites L., Origanum minutiflorum, and honey on chronic obstructive pulmonary disease (COPD). The study groups were classified as follows: Control (n=6), Sham (n=8), Origanum onites L. (n=8), Origanum minutiflorum (n=8), and Honey (n=8). After a 15-day treatment with origanum species and honey, the levels of CD3+, CD4+, CD8+, blood gas parameters (pH, pCO₂, pO₂, HCO₃⁻, sO₂), IL-1α, IL-33, HMGB1, MMP-9, and TIMP-1 were evaluated, along with histopathological findings. Significant differences were observed between the groups in CD3+ (p=0.017) and CD8+ (p=0.03) levels, whereas no significant difference was found in CD4+ levels (p=0.33). In blood gas measurements, the sham group exhibited a tendency toward deterioration in pH (p=0.005) and pCO₂ (p=0.018) values after treatment, whereas in the treatment groups, pH improved (Origanum onites L. p=0.015; Origanum minutiflorum p=0.012; Honey p=0.007) and pCO₂ decreased (Origanum onites L. p=0.048; Origanum minutiflorum p=0.001). A significant increase in pO₂ levels was observed in the Origanum onites L. (p=0.012) and Honey (p=0.013) groups, whereas no statistically significant difference was found in the Origanum minutiflorum (p=0.072). The Honey group showed a significant increase in sO₂ levels (p=0.024). The IL-1α levels in the Origanum minutiflorum showed a significant decrease compared to the sham and control groups (p<0.05). IL-33 levels were significantly different between the Origanum minutiflorum and Honey groups compared to the sham group (p<0.05). HMGB1 levels were significantly higher in the sham group than in other groups (p<0.05). MMP-9 levels were highest in the sham group but significantly decreased in the treatment groups (p<0.05). TIMP-1 levels were highest in the Honey group and lowest in the sham group, with a statistically significant difference between them (p<0.05). Histopathological analysis revealed that the degree of emphysema was highest in the sham group and lowest in the Honey group (p<0.05). Inflammation scores showed a decreasing trend in all treatment groups compared to the sham group (p>0.05). Lymphoid accumulation was observed only in the sham group, whereas fibrosis and granuloma were not detected in any group. Treatment with origanum species and honey demonstrated significant potential in improving inflammation, the protease-antiprotease balance, and gas exchange parameters in an experimental COPD model. Notably, the Origanum minutiflorum group was distinguished by its reduction in IL-1α and MMP-9 levels, whereas the Honey group was effective in increasing TIMP-1 levels and reducing the emphysema score. These findings suggest that natural products may serve as supportive or complementary therapeutic strategies in the pathogenesis of COPD.