Influence of hypercalcemia in the formation of tympanosclerosis in rats.
OBJECTIVE
Hypercalcemia is thought to perform an important role in the etiopathogenesis of tympanosclerosis. The purpose of the present study was to assess the influence of hypercalcemia in the development of tympanosclerosis in rats with or without acute otitis media.


BACKGROUND
The pathogenesis of tympanosclerosis is still unclear. Histologically, it is characterized by a hyaline degeneration in the lamina propria of the middle ear and mastoid mucosa and may lead to a calcification process. The process of calcification is similar to that of other pathologically calcified tissues, such as vessels, heart valves, cornea, and others, which depend on calcium serum levels.


METHODS
Twenty-four Wistar rats were divided into two different groups, with one group submitted to hypercalcemia status through calcium diet supplementation and the other used as a control group (normal calcium content diet). Both were submitted to induction of tympanosclerosis by inoculation of Streptococcus pneumoniae on the right middle ear only. Otomicroscopy was conducted every 15 days, and after 7 weeks of inoculation, the animals were killed and the tympanic bullae were resected to be analyzed through light and electron microscopy.


RESULTS
The group submitted to hypercalcemia presented a prevalence of tympanosclerosis of 25% against 16.7% in the control group, presenting a relative risk of 1.27 (p=0.72).


CONCLUSIONS
The results suggest that hypercalcemia can have an influence in the development of tympanosclerosis.
de Carvalho Leal
Mariana
M
Department of Otorhinolaryngology, University of São Paulo School of Medicine, São Paulo, Brazil. marianacleal@hotmail.com
Ferreira Bento
Ricardo
R
da Silva Caldas Neto
Silvio
S
Caldas
Nelson
N
Alves Peixoto
Christina
C
Delgado Lessa
Fábio José
FJ
Souza Leão
Rodrigo Souza
RS
Bezerra
Thiago
T
D000208:Acute Disease; D000818:Animals; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D006934:Hypercalcemia / Q000150:complications*; D046529:Microscopy, Electron, Transmission; D008859:Microscopy, Polarization; D010033:Otitis Media / Q000150:complications; D010040:Otosclerosis / Q000209:etiology* / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D013296:Streptococcus pneumoniae / Q000472:pathogenicity