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    β2-Microglobulin exacerbates neuroinflammation, brain damage, and cognitive impairment after stroke in rats
  • Figure 2|Cerebral stroke leads to an increase in β2M in rats. 

    We performed enzyme-linked immunosorbent assays, immunofluorescent staining, and western blotting to determine whether ischemic-hypoxic brain injury resulted in changes in β2M levels in sera, CSF, and brain tissue at 3 hours and 1, 3, 7, and 14 days post-MCAO. CSF (P < 0.0001 at 3 hours, P = 0.024 at 1 day) and serum β2M (P < 0.0001 at 3 hours, P = 0.016 at 1 day, P = 0.010 at 3 days, P = 0.0071 at 7 days) levels were significantly elevated in the model rats, peaked at 3 hours after MCAO, and gradually returned to normal levels at 3 and 14 days, respectively (Figure 2A and B). In addition, the protein expression of β2M (P = 0.02 at 3 hours, P < 0.0001 at 1 day, P = 0.0179 at 3 days; Figure 2C and D) and β2M-positive cell numbers (P < 0.0001 at 3 hours, P < 0.0001 at 1 day, P < 0.0001 at 3 days, P < 0.0001 at 7 days, P = 0.0035 at 14 days; Figure 2E and F) were also markedly increased in the ischemic penumbra. As shown in Figure 2G, β2M was mainly expressed in NeuN-positive neurons. Our results suggest that ischemic stroke leads to an enhancement of β2M expression in rats.


    Figure 3|β2M is silenced by lentivirus-mediated RNA interference.  

    To explore the role of β2M in neurological function and neuroinflammation of MCAO rats, RNA interference was used to silence the β2M gene. Both the number of β2M-positive cells (P = 0.0011; Figure 3A and B) and β2M protein levels (P = 0.0002; Figure 3C) were decreased in the ischemic penumbra of the MCAO rats after β2M shRNA treatment compared with those in the SC shRNA-treated rats. 


    Figure 6|β2M knockdown inhibits glial activation after cerebral ischemia.  

    Representative images of hematoxylin-eosin staining in Figure 6A show normal morphology of neuronal cells in the cerebral cortex of sham rats. However, cell loss, cells showing nuclear condensation with dark staining, and apparent inflammatory cell infiltration were detected in the lateral ischemic brains of MCAO rats. β2M knockdown alleviated hypoxia-ischemia–induced cell death and inflammatory cell infiltration. Glial cell activation was detected by GFAP and IBA-1 immunofluorescent staining (Figure 6B and C). Compared with those in the sham group, ischemia increased the number of GFAP+ (all P < 0.0001) and IBA-1+ (MCAO vs. sham, P < 0.0001; MCAO+ β2M RNAi vs. sham, P = 0.0048; MCAO+ SC vs. sham, P < 0.0001) cells. However, inhibition of β2M markedly decreased the numbers of astrocytes (P < 0.0001) and microglial cells (P = 0.0323; Figure 6D and E). Furthermore, the protein levels of GFAP (P = 0.0006) and IBA-1 (P = 0.0088) increased after MCAO compared with those in the sham group. However, β2M knockdown decreased the levels of GFAP (P = 0.0073) and IBA-1 (P = 0.0164) compared with those in the SC group (Figure 6F and G). 


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  • 发布日期: 2022-08-29  浏览: 134
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