Protective effect of salidroside on lung tissue in rats exposed rapidly to high altitude

To study the protective effect and mechanism of salidroside on lung tissue of rats exposed rapidly to high altitude.

Thirty-six Wistar male rats were randomly divided into blank control group, model control group, Rhodiola rosea capsule (137 mg/kg) group, salidroside low-dose (14 mg/kg), medium-dose (28 mg/kg) and high-dose (56 mg/kg) groups, with 6 rats in each group. After 5 continuous days of drug administration in the plain lab, rats were rapidly moved to 4010 m plateau field lab. After exposure to hypoxia condition for 3 days the blood gas indexes were detected; the serum levels of inflammatory factors were measured by enzyme linked immunosorbent assay (ELISA); the oxidative stress index of lung tissue was measured; the pathological changes of lung tissue were observed by microscopy with hematoxylin and eosin (HE) staining; and the expression of occludin in lung tissues was determined by western blotting.

Compared with blank control group, arterial oxygen saturation (SaO ₂), arterial oxygen partial pressure (PaO ₂), blood pH, standard bicarbonate (SBC) and actual bicarbonate levels in model control group were significantly decreased, and hemoglobin level was significantly increased (all P<0.05). In the model control group, the contents of mast cell protease (MCP) 1, interleukin (IL)-6 and IL-1β were significantly increased, while the contents of interferon-γ were significantly decreased (all P<0.01). The contents of glutathione and total superoxide dismutase in the lung tissues of model control group were significantly decreased, while the content of malondialdehyde was significantly increased (all P<0.01). After Rhodiola rosea and salidroside were given, SaO ₂, pH, hemoglobin, SBC and actual bicarbonate were improved compared with the model control group. Compared with the model control group, the Rhodiola rosea group and salidroside groups had different degrees of improvement in the contents of the above inflammatory factors and oxidative stress indexes, and the salidroside groups had better improvement in MCP-1 and IL-6 than the Rhodiola rosea group. HE staining showed that, after the administration of Rhodiola rosea capsules and salidroside at low, medium and high doses, the hypoxic injury was significantly improved, the cell wall gradually became thinner, and the alveolar wall gradually became complete. The expression of occludin in the model control group was lower than that in the blank control group ( P<0.05), while the expression of occludin in the salidroside high-dose group was significantly higher than that in the model control group ( P<0.01).

Salidroside can improve the abnormality of blood gas index, hypoxia symptoms and acid-base balance disorder, dysregulation of inflammatory factors caused by hypoxia in rats, and improve lung tissue injury and oxidative stress injury, which has a protective effect on lung tissue injury of rats exposed rapidly to the high-altitude plateau, and the effect is better than Rhodiola rosea capsule on the whole.