Venous Shunt Versus Venous Ligation for Vascular Damage Control: The Immunohistochemical Evidence.
BACKGROUND
To evaluate the expression of immunohistochemical markers of tissue ischemia (iNOS, eNOS, and HSP70) in a vascular damage control experimental model to determine if a venous temporary vascular shunt insertion leads to a better limb perfusion when compared with the ligature of the injured vein.


METHODS
Experimental study in male Sus Scrofa weighting 40 Kg. Animals were distributed into 5 groups: group 1 animals were submitted to right external iliac artery (EIA) shunting and right external iliac vein (EIV) ligation; group 2 animals were submitted to right EIA shunting and right EIV shunting; group 3 animals were submitted to right EIV ligation; group 4 animals were submitted to right EIV shunting; group 5 animals were not submitted to vascular shunting or venous ligation. Transonic Systems flowmeters were used to measure vascular flow on right and left external iliac vessels, and i-STAT (Abbot) portable blood analyzer was used for EIVs blood biochemical analysis. An initial baseline register of invasive arterial pressure, iliac vessels flow, and venous blood analysis was performed. Arterial pressure and iliac vessels flow were taken immediately after right iliac vessels shunting or ligation. Then, hemorrhagic shock was induced by continuous 20 mL/min blood withdraw from the external right jugular vein whereas arterial blood pressure and iliac vessels flow registers were taken every 10 min, and blood samples from EIVs were obtained every 30 min until the vascular flow through right EIA (or through the shunt inserted into the right EIV for group 4 animals) became inexistent or until the animal's death. After the end of the experiments, bilateral hind limb's biopsies were obtained for immunohistochemical analysis. Using image editing and analysis software, the expression of iNOS, eNOS, and HSP70 (3 well-known ischemic associated immunohistochemical markers) was assessed. The mean expression of each marker in the right hind limb was compared between groups. For statistical analysis, Microsoft Office Excel 2007 and BioEstat 5.0 (2007) were used.


RESULTS
Immunohistochemical analysis showed no difference regarding the iNOS expression; nevertheless, both eNOS and HSP70 expression were statistically more intense (P < 0.05) on group 1 (eNOS = 1.32; HSP70 = 15.05) than on group 2 (eNOS = 0.018; HSP70 = 8.56).


CONCLUSIONS
The higher expression of eNOS and HSP70 in the right hind limbs of group 1 animals (arterial shunt and venous ligature) than group 2 animals (arterial shunt and venous shunt) suggests that venous ligation is associated with more intense ischemic histological findings than venous shunting.
Department of Surgery, Federal University of São Paulo (UNIFESP), São Paulo, Brazil. Electronic address: adenauerjunior@gmail.com.
Adenauer Marinho de Oliveira
AMO
Góes Junior
Department of Surgery, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
Simone de Campos Vieira
SCV
Abib
Department of Surgery, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
Maria Teresa de Seixas
MTS
Alves
Department of Surgery, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
Paulo Sérgio Venerando da Silva
PSVDS
Ferreira
Department of Surgery, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
Mariseth Carvalho de
MC
Andrade
D000818:Animals; D062186:Arterial Pressure; D001783:Blood Flow Velocity; D004195:Disease Models, Animal; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006614:Hindlimb; D007083:Iliac Artery / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D007084:Iliac Vein / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D007150:Immunohistochemistry; D007511:Ischemia / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008026:Ligation; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D012039:Regional Blood Flow; D012771:Shock, Hemorrhagic / Q000503:physiopathology; D034421:Sus scrofa; D013997:Time Factors; D014656:Vascular Surgical Procedures; D057772:Vascular System Injuries / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*
D018840:HSP70 Heat-Shock Proteins; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III