Tibetan medicine Duoxuekang ameliorates hypobaric hypoxia-induced brain injury in mice by restoration of cerebrovascular function.

Ethnopharmacological Relevance: Duoxuekang (DXK, ཁྲག་འཕེལ་བདེ་བྱེད།) is a clinical experience prescription of CuoRu-Cailang, a famous Tibetan medicine master, which has effective advantages in the treatment of hypobaric hypoxia (HH)-induced brain injury. However, its underlying mechanisms remain unclear.

Aim Of The Study: The present study was designed to investigate the effects of DXK on cerebrovascular function of HH-induced brain injury in mice.

Materials And Methods: DSC-MR imaging was used to evaluate the effect of DXK on the brain blood perfusion of patients with hypoxic brain injury. HPLC analysis was used to detect the content of salidroside, gallic acid, tyrosol, corilagin, ellagic acid, isorhamnetin, quercetin and gingerol in DXK. The model of HH-induced brain injury in mice was established by an animal hypobaric and hypoxic chamber. The BABL/c mice were randomly divided into six groups: control group, model group, Hongjingtian oral liquid group (HOL, 3.3 ml/kg) and DXK groups (0.9, 1.8 and 3.6 g/kg). All mice (except the control group) were intragastrically administrated for a continuous 7 days and put into the animal hypobaric and hypoxic chamber after the last intragastric administration. Hematoxylin-eosin staining was employed to evaluate the pathological changes of brain tissue. Masson and Weigert stainings were used to detect the content of collagen fibers and elastic fibers of brain, respectively. Routine blood test and biochemical kits were used to analyze hematological parameters and oxidative stress indices. Immunofluorescence staining was applied to detect the protein levels of VEGF, CD31/vWF and α-SMA.

Results: The results of DSC-MR imaging confirmed that DXK can increased CBV in the left temporal lobe while decreased MTT in the right frontal lobe, right temporal lobe and right occipital lobe of the brain. DXK contains salidroside, gallic acid, tyrosol, corilagin, ellagic acid, isorhamnetin, quercetin and gingerol. Compared with the model group, DXK can ameliorate the atrophy and deformation, and increase the number of pyramidal neurons in hippocampal CA3 area and cortical neurocytes. Masson and Weigert stainings results revealed that DXK can significantly increase the content of collagen fibers and elastic fibers in brain. Routine blood test results demonstrated that DXK can dramatically decrease the levels of WBC, MCH and MCHC, while increase RBC, HGB, HCT, MCV and PLT in the blood samples. Biochemical results revealed that DXK can markedly increase SOD, CAT and GSH activities, while decrease MDA activity. Immunofluorescence revealed that DXK can notably increase the protein levels of VEGF, CD31/vWF and α-SMA.

Conclusions: In conclusion, this study proved that DXK can ameliorate HH-induced brain injury by improving brain blood perfusion, increasing the number of collagen and elastic fibers and inhibiting oxidative stress injury. The underlying mechanisms may be involved in maintaining the integrity of cerebrovascular endothelial cells and vascular function. However, further in vivo and in vitro investigations are still needed to elucidate the mechanisms of DXK on regulating cerebral blood vessels.