Influence of necrostatin-1 in microglia activation and inflammatory factor levels after cerebral ischemia/reperfusion damage in rats / 中华神经医学杂志

ABSTRACT

Objective To investigate the influence of necroptosis pathways in microglia activation and inflammatory factor levels in cerebral ischemia/reperfusion (I/R) injury in rats and their significances.Methods A modified suture method was used to establish the models of middle cerebral artery I/R in rats.(1) SD rats according to the random number table were divided into cerebral I/R 6 h group,cerebral I/R 12 h group,cerebral I/R 24 h group,and cerebral I/R 72 h group (n=6);the expression of ionized calcium binding adaptor molecule-1 (iba-1) was detected by immunohistochemical staining,and time points enjoyed obvious iba-1 expression were selected according to the experimental results.(2) SD rats were randomly divided into sham operation group,cerebral I/R group,80 nmol necrostatin-1 (Nec-1) intervention group and 160 nmol Nec-1 intervention group (n=6),and the Nec-1 intervention was given 2 h after ischemia;Longa method was used to evaluate the neurological function scores and TTC method was used to detect the infarct volume;and the appropriate dosages of Nec-1 were selected according to these results.(3) SD rats were randomly divided into sham operation group,cerebral I/R group,solvent group and Nec-1 intervention group (n=6),and Nec-1 or DMSO intervention was given 2 h after ischemia.HE staining was used to observe the survival and proliferation ofmicroglias around the infarction tissues;immunohistochemical staining was used to detect the iba-1 expression surrounding the infarction tissues;immunohistochemistry and Western blotting were employed to observe the cytokine tumor necrosis factor (TNF)-α and interleukin (IL)-1β and glia-derived neurotrophic factor (GDNF) expressions.Results (1) The iba-1 expression at cerebral I/R 24 h group was significantly increased as compared with that in other groups (P＜0.05).(2) As compared with those in the cerebral I/R group,the neurological function scores and infarct volume were significantly decreased in the 80 nmol Nec-1 intervention group and 160 nmol Nec-1 intervention group (P＜0.05);more obvious changes were noted in the 160 nmol Nec-1 intervention group as compared with those in the 80 nmol Nec-1 intervention group,with significant difference (P＜0.05).(3) HE staining showed peri-infarct tissue inflammatory cell infiltration,reduced neuron number,cell body shrinkage and nuclear pyknosis in the cerebral I/R group,while these changes were less obvious in the Nec-1 intervention group;as compared with cerebral I/R group,the Nec-1 intervention group had significantly decreased expressions of iba-1,TNF-α,IL-1 β and GDNF (P＜0.05).Conclusion Necroptosis pathway involves in the activation ofmicroglias after I/R injury in rat brains;Nec-1 inhibits the activation of microglia,and reduces the neuronal damage by regulating inflammatory cytokines.