Effects of early-life LiCl-pilocarpine-induced status epilepticus on memory and anxiety in adult rats are associated with mossy fiber sprouting and elevated CSF S100B protein.
OBJECTIVE
This study investigated putative correlations among behavioral changes and: (1) neuronal loss, (2) hippocampal mossy fiber sprouting, and (3) reactive astrogliosis in adult rats submitted to early-life LiCl-pilocarpine-induced status epilepticus (SE).


METHODS
Rats (P15) received LiCl (3 mEq/kg, i.p.) 12-18 h prior pilocarpine (60 mg/kg; s.c.). At adulthood, animals were submitted to behavioral tasks and after the completion of tasks biochemical and histological analysis were performed.


RESULTS
In SE group, it was observed an increased number of degenerating neurons in the CA1 subfield and in the hilus of animals 24 h after SE. At adulthood, SE group presented an aversive memory deficit in an inhibitory avoidance task and the animals that presented lower latency to the step down showed a higher score for mossy fiber sprouting. In the light-dark exploration task, SE rats returned less and spent less time in the light compartment and present an increased number of risk assessment behavior (RA). There was a negative correlation between the time spent in the light compartment and the score for mossy fiber sprouting and a positive correlation between score for mossy fiber sprouting and number of RA. LiCl-pilocarpine-treated animals showed higher levels of S100B immunocontent in the CSF as well as a positive correlation between the score for sprouting and the GFAP immunocontent in the CA1 subfield, suggesting an astrocytic response to neuronal injury.


CONCLUSIONS
We showed that LiCl-pilocarpine-induced SE during development produced long-lasting behavioral abnormalities, which might be associated with mossy fiber sprouting and elevated CSF S100B levels at adulthood.
de Oliveira
Diogo Losch
DL
Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rio Grande do Sul, Brazil. losch@ufrgs.br
Fischer
Alice
A
Jorge
Renan Sanna
RS
da Silva
Mariane Castro
MC
Leite
Marina
M
Gonçalves
Carlos Alberto
CA
Quillfeldt
Jorge Alberto
JA
Souza
Diogo Onofre
DO
e Souza
Tadeu Mello
TM
Wofchuk
Susana
S
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development; D001007:Anxiety / Q000139:chemically induced; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D005239:Fear / Q000187:drug effects / Q000523:psychology; D006624:Hippocampus / Q000187:drug effects / Q000473:pathology; D018021:Lithium Chloride / Q000494:pharmacology; D008568:Memory / Q000187:drug effects / Q000502:physiology; D019599:Mossy Fibers, Hippocampal / Q000187:drug effects / Q000503:physiopathology; D009414:Nerve Growth Factors / Q000097:blood; D010862:Pilocarpine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood; D013226:Status Epilepticus / Q000097:blood / Q000139:chemically induced* / Q000503:physiopathology
D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579158:S100b protein, rat; D010862:Pilocarpine; D018021:Lithium Chloride