Changes after dynamic observation of ultrastructural cerebral infarction in renovascular hypertensive rats

Objective To study the ultrastructural damages of brain tissues dynamically after middle cerebral artery obstruction (MCAO). Methods A middle cerebral artery obstruction (MCAO) model was reproduced in renal vascular hypertensive rats (RHR). Brain tissues in different locations were collected for eight times in row, from two hours to seven days after establishment of the animal model. Results The changes occurred in the whole brain after focal cerebral ischemia. The severity of impairment and time of emergence differed with the location sampled. The earliest in the infarcted region with necrosis was considered the major change and completely irreversible damage. The next was seen in marginal regions, mainly with microvascular collapse, formation of microthrombi, and partial necrosis of brain cells and was considered partially reversible damage. The last was in distant and contralateral hemisphere, mainly with reversible swelling of endothelial cells and astrocytes. Changes in the MCAO models reproduced by RHR models were much similar to the clinical pathological changes in cerebral infarction based on the hypertensive cerebrovascular impairment, and it was regarded as a relatively ideal model for studying focal ischemic cerebral impairment. Conclusion Dynamic changes of cerebral ultrastructure in which microvascular impairment plays an important role suggest that clinical therapy cannot only be focused on infarction foci, but also on the whole brain with comprehensively effective measurements.