No effect of ablation of surfactant protein-D on acute cerebral infarction in mice

Background: crosstalk between the immune system in the brain and the periphery may contribute to the long-term outcome both in experimental and clinical stroke. although,the immune defense collectin surfactant protein-d (sp-d) is best known for its role in pulmonary innate immunity,sp-d is also known to be involved in extrapulmonary modulation of inflammation in mice. we investigated whether sp-d affected cerebral ischemic infarction and ischemia-induced inflammatory responses in mice.methods: the effect of sp-d was studied by comparing the size of ischemic infarction and the inflammatory and astroglial responses in sp-d knock out (ko) and wild type (wt) mice subjected to permanent middle cerebral artery occlusion. sp-d mrna production was assessed in isolated cerebral arteries and in the whole brain by pcr,and sp-d protein in normal appearing and ischemic human brain by immunohistochemistry. changes in plasma sp-d and tnf were assessed by elisa and proximity ligation assay,respectively.results: infarct volumetric analysis showed that ablation of sp-d had no effect on ischemic infarction one and five days after induction of ischemia. further,ablation of sp-d had no effect on the ischemia-induced increase in tnf mrna production one day after induction of ischemia; however the tnf response to the ischemic insult was affected at five days. sp-d mrna was not detected in parenchymal brain cells in either naïve mice or in mice subjected to focal cerebral ischemia. however,sp-d mrna was detected in middle cerebral artery cells in wt mice and sp-d protein in vascular cells both in normal appearing and ischemic human brain tissue. measurements of the levels of sp-d and tnf in plasma in mice suggested that levels were unaffected by the ischemic insult. microglial-leukocyte and astroglial responses were comparable in sp-d ko and wt mice.conclusions: sp-d synthesis in middle cerebral artery cells is consistent with sp-d conceivably leaking into the infarcted area and affecting local cytokine production. however,there was no sp-d synthesis in parenchymal brain cells and ablation of sp-d had no effect on ischemic cerebral infarction. © 2014 lambertsen et al.; licensee biomed central ltd.