MiR-29b expression is downregulated after MCAO injury while miR-29b inhibition exacerbates cerebral injury
We investigated the effect of intravenous injection of miR-29b antagomir by measuring the infarct volume and neurological deficits after MCAO injury. First, we found decreased miR-29b levels in the ischemic brain and leukocytes at 24 h in MCAO rats (Figure 2A, P < 0.05). Second, there was downregulated miR-29b expression in leukocytes after miR-29b antagomir injection (Figure 2B, P < 0.05). Third, TTC staining showed that miR-29b antagomir treatment increased the cerebral infarct volume and oedema volume compared with that in MCAO rats (Figure 2C, P < 0.05). MiR-29b antagomir significantly promoted MCAO-induced neurological deficiency (Figure 2C, P < 0.05). Fourth, miR-29b antagomir increased the number of cortical TUNEL-positive cells in MCAO rats (Figure 2D, P < 0.05). Fifth, H19 siRNA promoted miR-29b expression, which indicated that H19 interacts with miR-29b in the leukocytes of MCAO rats (Figure 2B, P < 0.05).