[Effect of L-arginine on the changes of cerebral microcirculation following craniocerebral missile wound at early stage in cats].

OBJECTIVE:To study the alterations of cerebral microcirculation and the effect of L-Arginine after craniocerebral missile wound (CMW) at early stage in cats. METHODS:The CMW animal model in cat was constructed by Carey method. Altogether 12 mongrel cats with either sex were divided into the CMW group and the L-Arginine treatment group. The caliber (D), velocity (V) and blood flow (Q) of pial microvessels and pathological examination of brain tissue at 10 min before CMW and from 5 min to 5 h after CMW were evaluated in each group. RESULTS:1. In CMW group, although the Da, Va and Qa of pial arteriole decreased from 5 to 20 minutes, Da and Qa elevated at 90 minutes after CMW. There were no significant changes in the Dv of pial venule, but the levels of Vv and Qv were lower at 5 min and 20 min after CMW. Qv increased from 45 min to 3 h after CMW. The pial venules were in congestion situation. 2. In the L-Arginine treatment group, the pial aterioles persistently dilated after CMW. The blood flow of pial aterioles increased at 20 min after CMW and the higher level lasted 5 h. Similarly, the dilation of pial venules was observed, and the blood flow increased at 20 min after the injury, followed by venules constriction temporarily. 3. Petechial hemorrhage, microthrombosis and nerve cell swelling were found in the cortex on the opposite side of the trauma area. The pathological changes were less severe in the L-Arginine treatment group than those in the CMW group. CONCLUSION:At the early stage after CMW, there are obstructions to cerebral microcirculation, which induce brain ischemia, hypoxia and secondary failure of cerebral function. The mechanism by which L-Arginine alleviates the impaired cerebral microcirculation may lie in the vascular activation of L-Arginine-NO system.