Establishment of cerebral infarction model in rabbits induced by photochemical injury

Yixiang SHAO; Shunxing ZHU; Li DING; Xiangyang ZHU

ABSTRACT

BACKGROUND:

Cerebral infarctional animal model provide basis for studying human cerebral infarction(CI). There are two traditional CI models, one is reproduced by craniotomy or electro-coagulation by which supplying artery are blocked, another is achieved by embolus or water gelatin micro-thrombosis. But both are difficult to perform and results were instable, which limit the application. Photochemical injury is a novel way to reproduce CI model on experimental animals.

OBJECTIVE:

To explore a new method of experimental research of local cerebral infarction model which is induced by photochemical injury in rabbits.

DESIGN:

Single sample study

SETTING:

Experimental Animal Center of Nantong University.MATERIALS This study was conducted at the Experimental Animal Center of Nantong University from May to December 2003 (secondary laboratory). Totally 63 Japanese flap-eared rabbits, with birth age of 10-12 month, 33 females and 30 males, with body mass of 1.7-3.3 kg, were randomly selected.

METHODS:

After anaesthetized, rabbits were cut at the skin for 2 cm long at the crossing of skull center and posterior canthus, skull was exposed and periosteum was separated, then a round skull window with diameter of 0.5 cm was drilled at 0.5 cm left or (right) to sagittal suture and 0.5 cm posterior to coronal suture, after that, 35 g/L rose Bengal was slowly injected from ear-edge vein in dosage of 1 mL/kg by once. About 3minutes later, cold light source (wave length of 540 nm, power of 140 lx)was used to cast light directly onto the skull window for consecutively 8minutes, then incision was sutured. At postoperative 24 hours, neurological defects were scored in five grades [0 score represent no neural impairments; 1 score the left posterior limbs displayed decreased muscular tension and attenuated contraction reflex; 2 scores the left posterior limbs were paralyzed, displaying obvious abduction; 3 scores rabbit displayed obvious adductive drag with body leant to the opposite side; 4 scores unable to walk and unconsciousness], rabbits were put to death at postoperative 48 hours, infarctional area and volume were determined and pathological changes was also observed.MAIN OUTCOME

MEASURES:

Limb movement, infarctional area and volume and pathological changes.

RESULTS:

CI mode was successfully established on 59 rabbits, the sucmean infarctional area was (0.465±0.012) cm2, and the mean volume changes Infarctional focus displayed typical pathological changes such as impairment, effusion and inflammation. Gentle impairment could be observed in 22 rabbits (37%), medium in 32 rabbits (54%) and severer in 5rabbits (9%).infarction model has multiple advantages, such as easy performance, quick and good repeatability, it can be used to reproduce experimental models for for a long time with low mortality, benefiting for researches on chronic tional size and depth are under control, meeting the need of researches on observed in photochemical injury, which provide basis for study on the efBut there was still some

limitations:

Since thrombosis was induced at the terminal artery, unfit for the study of lateral circulation and reperfusion;however it was found more similar to human microvascular diseases, thereby incapable of explaining the pathogenesis of other ischemic strokes.