Intracerebral transplantation of carotid body in rats with transient middle cerebral artery occlusion

Recent laboratory and clinical studies demonstrate therapeutic efficacy of intracerebral transplantation of carotid body (CB) in Parkinson's disease, possibly through secretion of neurotrophic factors. Here, we examined the role of CB in experimental stroke. In the first experiment, we hypothesized that removal of CB would exacerbate cerebral infarction and stroke-related behavioral deficits. Eight-week-old, male Sprague-Dawley rats were randomly divided into two groups: stroke with intact CB and stroke with surgically removed CB. We used the stroke model of temporary middle cerebral artery occlusion. The ipsilateral CB was removed in animals assigned to treatment group exposed to stroke with surgically removed CB. Behavioral tests, using the elevated body swing test, were conducted at days 1-3 after surgery. Cerebral infarction was visualized by TTC staining on day 3 post-surgery. The data revealed no significant differences in behavioral deficits and infarct volumes between the two groups. In the second experiment, CB cell suspension grafts or control adult tissue grafts were intracerebally transplanted into the ischemic penumbra immediately (within 1 h) after stroke surgery. The results revealed significant reduction of behavioral deficits and infarct volumes, accompanied by increased levels of neurotrophic factors, as detected by ELISA, in transplanted ischemic striatum collected from CB-grafted stroke animals. These observations suggest that surgical resection of CB in the periphery did not alter stroke pathology; however, CB when made available in the CNS, via intracerebral transplantation, could protect against stroke possibly through the synergistic release of neurotrophic factors. The present study extends the use of CB as efficacious graft source for transplantation.