Effect of LTA isolated from bifidobacteria on D-galactose-induced aging

Bifidobacteria are a natural part of the bacterial flora in the human body and have a symbiotic bacteria-host relationship with human beings. Aging is associated with reduced number of beneficial colonic bifidobacteria and impaired immunity. Lipoteichoic acid is a major constituent of the cell wall of bifidobacteria which is important for bacterial survival, growth, and function. The possible anti-aging effects of lipoteichoic acid isolated from bifidobacteria is presently unknown.

The aim of the present study was to investigate possible anti-aging effects of lipoteichoic acid isolated from bifidobacteria on senescent mice artificially induced by chronic injection of d-galactose and explore potential anti-aging's mechanisms.

Mice were artificially induced senescence by consecutive injection of d-galactose (100mg/kg) once daily for 7weeks and lipoteichoic acid from bifidobacterium bifidum, was simultaneously administered to them once a week by intraperitoneal infusion. Mice were sacrificed, blood and other samples were collected at the indicated time. Anti-oxidation activity in brain, histology of tissue, gene expression, lymphocyte's DNA damage and cytokine production of lymphocytes in vitro and in vivo were measured.

Lipoteichoic acid could significantly improve general appearance of the aging model mice, improve anti-oxidation activity in brain, increase IL-2 level and decrease TNF-alpha level in vitro and in vivo, respectively. Besides, LTA remarkably inhibited DNA damage in the both splenic lymphocytes and circulating lymphocytes. Moreover, LTA could decrease p16 expression while increase c-fos expression in the d-galactose treated mice.

Taken together, the results indicated, for the first time, that LTA could suppress the aging process via the following several mechanisms, including enhancement of anti-oxidation activity in brain, improvement of immune function and alteration of gene expression.