Herpes simplex virus type 1 infection of the rat enteric nervous system evokes small-bowel neuromuscular abnormalities.
OBJECTIVE
Infectious agents, such as neurotropic viruses, are proposed to disrupt the enteric neuromuscular system, leading to dysmotility, although the mechanisms are unknown. Our purpose was to assess whether herpes simplex virus type-1 (HSV-1) establishes an enteric-neuronal infection and induces gut dysmotility.


METHODS
Rats were inoculated with HSV-1 intranasally and after 4 weeks intragastrically. After 1-10 weeks, infection was determined by molecular analysis whereas neuromuscular function was evaluated by pharmacologic/electrical stimulation of longitudinal ileal segments and by gastrointestinal transit and by [(3)H]acetylcholine release measurements. Inflammation in the neuromuscular layer was assessed by myeloperoxidase and cytokine levels and by anti-CD3(+) immunohistochemistry.


RESULTS
After 1-10 weeks of intragastric inoculation, HSV-1 latency-associated messenger RNA transcripts were detected in the brain and in ileal neurons with no signs of illness or histologic gut abnormalities. By using a recombinant HSV-1 carrying the lacZ gene, HSV-1 virions were localized in myenteric ganglia by in situ X-gal staining. Interleukin-2 and IFN-gamma levels were increased significantly 1 and 6 weeks after inoculation. CD3(+) cells were found around the myenteric ganglia 6 weeks after inoculation. Smooth muscle responses to carbachol, CaCl(2), and gut transit were increased significantly after 1 and 6 weeks, whereas KCl- and electrical field stimulation-mediated contractions were modified significantly only 1-2 weeks after HSV-1 administration. The release of [(3)H]acetylcholine was reduced significantly in ileum segments after 1 and 6 weeks.


CONCLUSIONS
After intragastric inoculation, HSV-1 establishes a latent infection in the rat myenteric ganglia, which leads to gut dysmotility.
Brun
Paola
P
Department of Histology, Microbiology and Medical Biotechnologies, University of Padua, Padua, Italy.
Giron
Maria Cecilia
MC
Zoppellaro
Chiara
C
Bin
Anna
A
Porzionato
Andrea
A
De Caro
Raffaele
R
Barbara
Giovanni
G
Stanghellini
Vincenzo
V
Corinaldesi
Roberto
R
Zaninotto
Giovanni
G
Palù
Giorgio
G
Gaion
Rosa Maria
RM
Tonini
Marcello
M
De Giorgio
Roberto
R
Castagliuolo
Ignazio
I
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D017252:CD3 Complex / Q000032:analysis; D002122:Calcium Chloride / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D017615:Enteric Nervous System / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology* / Q000821:virology; D005769:Gastrointestinal Motility; D005772:Gastrointestinal Transit; D006561:Herpes Simplex / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology* / Q000821:virology; D018259:Herpesvirus 1, Human / Q000235:genetics / Q000472:pathogenicity*; D007082:Ileum / Q000294:innervation*; D018836:Inflammation Mediators / Q000378:metabolism; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D008297:Male; D035683:MicroRNAs / Q000378:metabolism; D009119:Muscle Contraction; D009469:Neuromuscular Junction / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology* / Q000821:virology; D009195:Peroxidase / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D017735:Virus Latency
D017252:CD3 Complex; D018836:Inflammation Mediators; D007376:Interleukin-2; D035683:MicroRNAs; C477253:latency associated transcript, herpes simplex virus-1; D011189:Potassium Chloride; D007371:Interferon-gamma; D002217:Carbachol; D009195:Peroxidase; D002122:Calcium Chloride; D000109:Acetylcholine