Effect of tetramethylpyrazine on Nissl bodies in cerebral neurons of rats with epilepsy

Xiaoqin ZHU; Xiaoqi YU; Shuisheng LEI

ABSTRACT

BACKGROUND:

Tetramethylpyrazine has the protective effect against the central nervous system injury. The structural changes in Nissl bodies were regarded as a marker of neuron injury.

OBJECTIVE:

To investigate the effect of tetramethylpyrazine on the structure and the quantity of Nissl bodies of cerebral neurons in rat with epilepsy.

DESIGN:

A comparative study.

SETTING:

It was conducted at the Physiological Department of Medical School of Xianning College.MATERIALS From September 2004 to March 2005, it was completed at the Anatomy Department of Tongji Medical College, Huazhong University of Science and Technology. Forty healthy SD rats aging 3-4 months, weighing (250±50) g and regardless of their gender, were selected.

METHODS:

Rats underwent anesthesia and craniotomy. Then their cerebral cortex were exposed for placing BL-410 Experimental System of Biological Function (TME, China) to record the bilateral EEG of the brain and the seizure in rats with penicillin-induced epilepsy group and the 10 mg/kg tetramethylpyrazine group, 20 mg/kg tetramethylpyrazine group and 40 mg/kg tetramethylpyrazine group. In control groups, the brains of rats were taken out at 1 hour after craniotomy. In penicillin-induced epilepsy group, their brains were taken out at 1 hour after penicillin-induced epilepsy. In 10 mg/kg tetramethylpyrazine group, 20 mg/kg tetramethylpyrazine group and 40 mg/kg tetramethylpyrazine group, after stable penicillin-induced epilepsy, tetramethylpyrazine was injected intraperitoneally at a dose of 10 mg/kg, 20 mg/kg and 40 mg/kg, respectively.When the greatest protective effect of tetramethylpyrazine appeared, the rats' brains were taken out. Brain sections were sliced. Nissl bodies were stained by thionine staining. Under light microscope, structures of Nissl bodies were observed and the images of Nissl bodies were quantitatively analyzed by HPIAS-1000 high acuity color pathologic diagram-writing analyzing system. In each group, the average absorbency of 15 fields was regarded as the average absorbency of Nissl bodies in that group.MAIN OUTCOME

MEASURES:

In all the groups, the structure and the quantity of Nissl bodies of cortical neurons in rats were studied.of the structure of Nissl bodies in external granular layer cells and external pyramidal layer cells. In control group, multi-layer blue-stained and clumplike or granule-like Nissl bodies could be observed. In penicillin-induced epilepsy group, Nissl bodies were completely resolved and disappeared. In 10 mg/kg tetramethylpyrazine group, Nissl bodies were partly or completely resolved. In 20 mg/kg tetramethylpyrazine group, the quantity of Nissl bodies was significantly increased as compared with those in penicillin-induced epilepsy group and the 10 mg/kg tetramethylpyrazine group. In 40 mg/kg tetramethylpyrazine group, the quantity and the structure of of the average absorbency of stained Nissl bodies in external granular layer cells and external pyramidal layer cells in rat cortex among all the groups.In penicillin-induced epilepsy group, the average absorbency were dramatically lower than that in control group (0.033±0.002, 0.756±0.035, t=4.93,P ＜ 0.01). In 20 mg/kg tetramethylpyrazine group and 40 mg/kg tetramethylpyrazine group, the average absorbency were significantly higher than that in penicillin-induced epilepsy group (0.435±0.011, 0.658±0.029, t=2.98,5.32, P ＜ 0.01). In 40 mg/kg tetramethylpyrazine group, the average absorbency were similar to that in control group (t=1.75, P ＞ 0.05).

CONCLUSION:

Tetramethylpyrazine can significantly elevated the concentration of Nissl bodies of neurons in rats with epilepsy. Changes in the structure and quantity of Nissl bodies of cerebral neurons may be closely associated with seizure, and tetramethylpyrazine can restore the structure and the quantity of Nissl bodies of neurons, regulate their functions and hereby, inhibit seizures.