Sensitivity of rabbit fibrochondrocytes to mycoplasmas

Abstract

Primary cell culture from rabbit meniscus (fibrochondrocytes-FcrC) was infected for 24 hours with different inocula (10 2 to 10 7 Colony Forming Units-CFU) of Mycoplasma hominis PG-21, M. pneumoniae FH and 1428 or M. arthritidis PG-6. The severity of the different obtained cytophatic effects-CPE was inoculum, Mycoplasma species and strain dependant. These bacteria were recovered from all infected FcrC and the SP4 medium for mycoplasmas also caused toxic effect on the FcrC. It was concluded that rabbit fibrochondrocytes were sensitive to mycoplasma infection, as well as to the SP4 mycoplasma medium. Mycoplasmas have between 200 to 400nm, lack the cell wall, self-replicate, are wide spread in nature and may cause diseases. Some biologic features of these bacteria explain partially their role in hosts. Many cytogenetic effects have been described in cell cultures infected accidentally or experimentally with mycoplasmas. Meantime the mycoplasmas can stress the infected cell and may not kill it. Although this infection in cell culture invalidates some laboratory results, still cell cultures are useful and important tools to study the biology of mycoplasmas and to minimize the use of experimental animals (6,8).In humans Mycoplasma pneumoniae is a well-documented respiratory pathogen. However, species from normal flora of oral or urogenital tract may cause usual or unusual infections but rarely cause death. Septic arthritis by mycoplasmas in humans is unusual and hypogamaglobulinaemia is almost always present (2).M. arthritidis is a natural arthrogenic species in rodents and produces joint disease by intravenous inoculation (15). However, the species isolated from human synovial fluids produce a similar disease in chimpanzee if inoculated Despite of the known effects of mycoplasmas on cell cultures and the joint disease caused by them in humans it was proposed to use as a choice the rabbit meniscus cell culture (16) in order to verify this cell sensitivity to M. hominis, M. pneumoniae and M. arthritidis. Mycoplasma hominis PG-21, M. hominis 1620 (synovial fluid isolate), M. pneumoniae-FH, M. pneumoniae 1428 (nasopharynx isolate) and M. arthritidis PG-6 were cultured in 100 mL of SP4 broth. Cultures were separated in aliquots of 1.0 mL, stored at -70°C and quantified for determination of Colony Forming Units-CFU after freezing (8). Fibrochondrocytes culture-FcrC was obtained from the meniscuses of knees (lateral and medial) of New Zealand rabbits with 120 day-old weighting between 1.5 and 2.0 Kg. The tissue was removed and washed in PBS pH 7.5 with 40mg/mL of gentamicin. Soon after it was transferred to a Minimum Essential Medium of Eagle, modified by Dulbecco (DMEM) in balanced saline

Experimental infection of BHK21 and Vero cell lines with different Mycoplasma spp.

“…The strains of M. orale , M. salivarium, M. arginini and M. hyorhinis were cultivated in 10 mL of SP4 broth at 37 °C (Nascimento e t al ., 2002). The growth of the microorganisms was confirmed due to the acidification of the pH in the broth, absence of turbidity, production of colonies looking like `fried eggs’ in SP4 agar plates and through polymerase chain reaction (PCR).…”

Quality Control of Biotechnological Inputs DetectingMycoplasma

“…The strains of M. orale, M. salivarium, M. arginini and M. hyorhinis, donated by Jorge Timenetsky of University of São Paulo, were cultivated in 10 mL of SP4 broth at 37ºC (Nascimento et al 2002). The growth of the microrganisms was confirmed due to the acidification of the pH in the broth, absence of turbidity and production of colonies looking like 'fried eggs' in SP4 agar plates.…”