Purpose To investigate the differential susceptibility to elastase-induced vertebrobasilar dolichoectasia (VBD) induction in two different mouse strains.

Materials and methods 25 milliunit elastase was injected into the cisterna magna in C57BL/6 J (n = 48) and 129/SvEv (SV129) (n = 48) mice by injection of. At 3, 7, 14 and 28 days following elastase injection, MicroFil® polymer perfusion was performed. The arterial tortuosity index (TI) and the percentage increase in the diameter were calculated for basilar artery (BA). Arterial samples were processed for conventional histology, immunostaining and matrix metalloprotease (MMP) expression using gel zymography. A ≥50% increase in diameter and TI ≥ 10 of BA were used to indicate success in achieving VBD. Robust ANOVA using the Huber M-estimator was used to compare the effects of strain and time on % BA increase and TI. Comparison of VBD formation between groups was performed using Fisher's exact test.

Results Successful VBD induction was noted in 67% (18 of 27) C57BL/6 J strains vs 0% (0 of 19) in SV129 strains (P < 0.001). VBD was not observed in sham-operated controls. No effect was seen as a function of duration. Both TI and diameter increase for BA were greater in the C57BL/6 J strain compared to SV129strain (56.3±16.4 vs 21.1±21.6 for diameter, 17.4±7.6 vs 10.4±3.8 for TI). Expression of pro- and active MMP 2 and −9 were elevated in elastase-injected C57BL/6 J animals compared to corresponding controls as well elastase-injected SV129 animals. C57BL/6 J subjects demonstrated arterial wall remodeling characterized by internal elastic lamina disruption, muscular layer discontinuity, inflammatory cell infiltration and high matrix metalloproteinases expression in the media.

Conclusion C57BL/6 J mice demonstrated greater susceptibility to VBD induction than SV129 mice.

Disclosures Y. Zhu: None. H. Xing: None. D. Dai: None. D. Kallmes: None. R. Kadirvel: None.