The Expression Of Parvalbumin And Claretinin In The Cortical Dysplasia Model Rats

Abjective:To get a message of the expression about parvalbumin and calretinin in the Cortical dysplasia (CD) model rats and investigate the effect in identify different types of CD and the pathogenesy of intractable epilepsy which induced by CD.Methods:Sprague-Dawley pregnant rats were given intraperitoneal injections of 1-3-bis-chloroethyl-nitrosourea (BCNU) ,15mg/kg ,on embryonic day 15 (E15) can induce CD in the offspring. We observed the growth and development of the brain and praxiology change in the offspring,used the warm-water-immerse to induce seizure, cortical histopathology was examined in the resulting pups at postnatal 30 day (P30). At the same time, form the results of immunocytochemistry , Immunofluorescence and RT-PCR ,we got the expression of parvalbumin and calretinin in the cortex .Results:①Compared to the control group rats,the model rats was lessen of brain weight and volume (P<0.05) ; the latency period before seizure was shorter (P<0.05) ;②Immunohistochemical Hdemonstrated that the density of parvalbumin-immunoreactive cells in the model rats was 37.28±2.72 cells/ field and 77.50±4.49 cells/ field in the control group rats, which reduced significantly (P<0.05) and have an altered spatial distribution , some parvalbumin-immunoreactive cells nodus appeared in the superficial layers of the cortex, but in the peripheral cortex of it ,the parvalbumin-immunoreactive cells reduced or disappeared .The calretinin-immunoreactive cells were similar to the control group;③Immunofluorescence technique showed that the density of the parvalbumin-immunoreactive cells was reduced and the size of which was increased in theⅣlayer of the cortex of CD rats;④Form the RT-PCR results, we got a reduced expression of parvalbumin-mRNA (P<0.05) , but the expression of calretinin -mRNA was similar to the control group.Conclusions:1 The parvalbumin can use for index to identify different types of CD;2 The abnormal density and distribution of GABAergic interneurons which express parvalbumin in the CD model rats may play a pivotal role in the pathophysiologic mechanisms of intractable epilepsy .