Establishment and assessment of modified cerebral palsy model in rats

Objective To construct a novel type of cerebral palsy model in rats with intraperitoneal injection of lipopolysaccharide(LPS) and sequential oxygen deficit from pregnancy 16th day to the end of pregnancy and chronic bilateral common carotid artery occlusion on the 28th day.Assessing by weight, behaviour, modified neurological severity score, and pathological changes and to explain the superiority of our model. Methods Twelve SD pregnant rats were randomly selected as the experimental group, 3 SD pregnant rats were selected as the control group.From 16 days of pregnant, the pregnant rats were injected with LPS by intraperitoneal injection.and received oxygen deficit in the experimental group, and the pregnant rats were received saline solution in the control group until delivery.On the postnatal 7th day, bilateral common carotid arteries were ligated in the experimental group.The weight, eye-opening time, grip test, rotarod test and pathological section of the brain of newborn rats in the both groups were detected. Results In the experimental group and the control group, the weight were (5.6±0.9)g and (6.2±0.8) g, the left eyes open day were (16.9±2.0) d and (13.0±2.0) d, the right eyes were (23.1±2.6) d and (13.7±1.7) d, respectively, there were significant differences between the both groups (all P<0.05). In the experimental group and the control group, the score in grip test were (2.7±0.8) scores and (1.5±0.4) scores and MNSS were (4.9±2.5) scores and (1.2±1.0) scores, there were significant differences (all P<0.01). Neurons arrange in disorder, the white matter is thinner and inflammatory cells infiltrated in the experimental group pups.However in control group, brain tissue patho-logy slices showed neurons in neat rows, the gray and write matters boundaries were clear, and the corpus callosum was mature. Conclusions In late pregnancy intraperitoneal injection LPS and hypoxia with postnatal bilateral common carotid artery ligation can build a stable lasting rat cerebral palsy model. Key words: Brain damage; Infection; Cerebral palsy; Hypoxia-ischemia; Behavior