Construction and evaluation of intracerebral capsular hemorrhage models in rats

Rufei DAI; Jun CAI; Ning LIU; Fengyi ZHU; Xiaoming LI

ABSTRACT

BACKGROUND:

A stable and exact animal model is the necessary tool and basis for studying hemorrhagic cerebrovascular diseases.

OBJECTIVE:

To establish and evaluate the intracerebral capsular hemorrhage models in rats.

DESIGN:

A randomized and controlled animal experiment.

SETTING:

Second Hospital Affiliated to Xuzhou Medical College; First Hospital Affiliated to Nanjing Medical University.MATERIALS This experiment was carried out in the animal experimental center of Nanjing Medical University during May to November 2002.Totally 35 SD rats were randomized into two groups experimental group (n=30) and sham-operation group (n=5).

METHODS:

① Autoblood was injected into the intracerebral capsule of rats to create intracerebral capsule hemorrhage models with stereotaxy in the experiment group. ②Scoring was conducted according to 5-point neurological scoring criteria from ZeaLonga, somatic sensation and motor function of rats were observed. ③Somatosensory evoked potential(SEP) of rats was detected pre- and post-operation under anesthetic state. ④ After determination of SEP, the rats were sacrificed under anesthetic state. Brains were taken out to made slices, then sections were stained with haematoxylin and eosin. Changes in haematoma and histomorphology were observed at the largest focus under optical microscope.MAIN OUTCOME

MEASURES:

①Nerve function scoring; ②Latent period of various waves of SEP; ③ Observation of brain tissue morphology.

RESULTS:

Totally 35 rats entered the stage of result analysis. ①Appearance of obvious paralysis of the rats suggested the modeling was successful. The successful rate of this experiment was 93.3%(28/30). Significant difference existed in neurological scoring between experimental group [(2.74±0.46)points] and sham-operation group (0 point)(P＜0.05). ②SEP showed that the latent periods of various waves of experimental group after operation were significantly delayed than those before operation and those of sham-operation group [P1 (15.72±0.78) ms, (10.69±0.52) ms, (10.73±0.48) ms;Nl (17.95±1.27) ms,(13.21±1.31) ms, (13.34±1.27) ms;N2(21.16±1.62) ms, (15.42±1.46) ms,(15.58±1.44) ms;N3(24.86±1.58) ms, (18.72±1.76) ms, (18.99±1.67) ms,P＜0.05]. ③In the shamoperation group, a few red blood cells were scattered in the peripheral area of needle channel were found, but hemorrhagic focus was not; In the experimental group, irregular or oval blood clots presented in the left internal capsule area. In about a low-fold visual field, brain tissue in the surrounding of hemorrhagic focus was loosened and swelled, and pathological changes were obviously severer than those in the sham-operation group.

CONCLUSION:

Intracerebral capsular hemorrhage induced by injection of autoblood with stereotaxy is more close to clinical situation, and it is easy to operate and has good reproducibility.