Challenging the surgical rodent hindlimb ischemia model with the miniinterventional technique

Purpose

To develop an interventional hindlimb ischemic model and compare its angiogenic effect versus surgical ligation (SL) and excision of the femoral artery in rats treated with transplantation of bone marrow mononuclear cells (MNCs) as an angiogenic stimulator.

Materials and Methods

Forty-eight Lewis rats randomly received interventional embolization (IE) with hydrogel wire or SL and excision of the right femoral artery. Rodents were intraarterially transplanted with 1.5 × 10⁷ MNCs in 500 μL medium from 24 isogenic donor rats. Functional and structural recovery was evaluated by laser Doppler imaging (LDI), cytokine/chemokine assay, and histologic staining.

Results

In vivo microscopic images showed significantly dilated vasa vasorum around the embolized segment of the right femoral artery at 3 days compared with disorganized tissue structure in the SL group. However, the LDI index was significantly higher in the SL group at 3 days compared with the IE group. LDI did not significantly differ between the two groups at 2 weeks after transplantation. Cytokine assay showed higher levels of interleukin (IL)–1α and IL-18 in the SL group; the IE group had higher levels of interferon-γ, IL-6, IL-13, and granulocyte colony-stimulating factor. Histologic examination demonstrated inflammatory infiltration near the incision within nerve fibers with dilated capillaries, showing nerve degeneration in the SL group. At 2 weeks, histologic analysis demonstrated massive scarring under the skin spreading into the musculature in the SL group.

Conclusions

A minimally invasive hindlimb ischemia model has been successfully developed that preserves tissue integrity and minimizes inflammation and confounding factors in the early stages of angiogenesis and arteriogenesis.