Protective effect of Portulaca oleracea extracts on hypoxic nerve tissue and its mechanism

The aim of this study was to investigate whether Portulaca oleracea (PO) extracts have hypoxic neuroprotective effects and if so, by what mechanism. After being orally administrated with the PO extracts or distilled water for seven days, adult male BALB/c mice were adapted to a normobaric low oxygen environment (10% oxygen and 90% nitrogen) for different time and then were sacrificed. The mouse cortices were used for histological analysis by hematoxylin and eosin (H-E staining). The activities of pyruvate kinase (PK), phosphofructokinase (PFK), lactic acid (LD) and the level of lactate dehydroenase (LDH) and ATP were detected, and the mRNA and protein levels of EPO in the cortices were analyzed. PC-12 cells and primarily cultured nerve cells were used for 3-(4,5-Dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay. The degree of LDH in the cell culture medium was tested. The results showed that the PO extracts enhanced the EPO mRNA and protein expression in the mouse cortices. Compared to the control group, the mouse in the group treated with the PO extracts by 1 g/d had significantly higher activities of PF, PFK, LDH and higher levels of ATP in the cortices, especially under the hypoxic environment for 24 hours. Histological analysis indicated that the extracts lessened the inflammation damage of the mouse brain. MTT assay results showed the PO extracts or the herb-containing serum raised the viability of the cells under the tested hypoxic conditions and decreased the degree of LDH in the culture medium in a dose-dependent manner. We thus demonstrated that the PO extracts had protective effects on hypoxic nerve tissue.