Quantification of vasospasm and neuronal apoptosis at PODs 7 and 15 in the TLR4 pathway. A. Vasospasm quantified by lumen radius/wall thickness on post-operative days (PODs) 7 and 15 in sham, intracerebroventricular (ICV)-injected lipopolysaccharide (LPS), wild type subarachnoid hemorrhage (SAH), TLR4−/− SAH, MyD88−/− SAH, and TRIF−/− SAH. Student’s t-test showed significantly increased vasospasm on POD 15 in Myd88−/− (P <0.01) and TRIF−/− on POD 7 (P <0.02). No difference between wild type SAH and TRIF−/− on POD 7 or wild type SAH and MyD88−/− on POD 15. For A and B, error bars are standard deviations and N = 4 for each group. B. Apoptotic neurons quantified in dentate gyrus at PODs 7 and 15 in sham, ICV-injected LPS, wild type SAH, Toll-like receptor 4 (TLR4)−/− SAH, MyD88−/− SAH, and TRIF−/− SAH. Student’s t-test on POD 7 resulted in significantly increased neuronal apoptosis in TRIF−/− (P <0.03) and in MyD88−/− on POD 15 (P <0.04). Furthermore, a significant increase in neuronal apoptosis exists between wild type (WT) SAH and ICV LPS on POD 7 by Bonferroni post-hoc comparison (P <0.04). No difference between wild type SAH and TRIF−/− on POD 7 or wild type SAH and MyD88−/− on POD 15.