Alleviation of brain edema by L-arginine following experimental subarachnoid hemorrhage in a rat model.

Decreased levels of nitric oxide play a role in the development of cerebral ischemia secondary to subarachnoid hemorrhage (SAH). The protective effect of L-arginine on brain edema following SAH was investigated in this study. Rats were divided randomly into a sham-operated, a SAH+saline group and a SAH+L-arginine group. At different time points, brain water content was determined using the wet and dry weight compared method. Brain sodium content, potassium content and calcium content were detected using an atomic absorption spectral photometer. Somatosensory evoked potentials (SEP) were also detected. It was found that rat SAH models were successfully replicated. In the SAH+saline group, brain water and sodium content were significantly higher at 6 h and 24 h than those in the sham-operated group, while brain potassium content was statistically lower than that in the sham-operated group. Brain calcium content increased from 1 h to 24 h after induction of SAH. SEP latency progressively delayed. In the SAH+L-arginine group, increases in brain water content, sodium content and calcium content, as well as decreases in brain potassium content, were not as obvious as in the SAH+saline group. L-arginine partly prevented a delay in SEP latency. In conclusion, L-arginine, a substrate of nitric oxide synthesis, may relieve brain edema in rats with experimental SAH.