BACKGROUND: Submandibular salivary glands (SMGs) synthesize, accumulate and secrete a large amount of epidermal growth factor (EGF) in mice. It is known that surgical removal of SMG (sialoadenectomy) alters cell turnover in the liver and exacerbates liver injury induced by lipopolysaccharide/galactosamine (LPS/GalN). RESULTS: Here we show that such increased hepatotoxicity is not the consequence of the lack of EGF production from SMG. On the contrary, it appears to be the consequence of an inadequate cytokine production by the liver of sialoadenectomized mice. Thus, we found that the increase of plasma tumour necrosis factor-alpha and interleukin-6 was slower in sialoadenectomized than in sham-operated mice. This is because of a decreased rate of production of both cytokines by the liver. We found that the increase of plasma corticosterone (CS) concentration is lower in sialoadenectomized than that in sham-operated mice. Adrenalectomy exacerbated liver injury induced by LPS/GalN. In these animals, sialoadenectomy did not further increase the effect of LPS/GalN. CONCLUSIONS: Our results suggest that the effect of sialoadenectomy on LPS/GalN-induced liver toxicity may be the consequence of an altered cytokine production by the liver and a reduced CS release from adrenal glands.
BACKGROUND: Submandibular salivary glands (SMGs) synthesize, accumulate and secrete a large amount of epidermal growth factor (EGF) in mice. It is known that surgical removal of SMG (sialoadenectomy) alters cell turnover in the liver and exacerbates liver injury induced by lipopolysaccharide/galactosamine (LPS/GalN). RESULTS: Here we show that such increased hepatotoxicity is not the consequence of the lack of EGF production from SMG. On the contrary, it appears to be the consequence of an inadequate cytokine production by the liver of sialoadenectomized mice. Thus, we found that the increase of plasma tumour necrosis factor-alpha and interleukin-6 was slower in sialoadenectomized than in sham-operated mice. This is because of a decreased rate of production of both cytokines by the liver. We found that the increase of plasma corticosterone (CS) concentration is lower in sialoadenectomized than that in sham-operated mice. Adrenalectomy exacerbated liver injury induced by LPS/GalN. In these animals, sialoadenectomy did not further increase the effect of LPS/GalN. CONCLUSIONS: Our results suggest that the effect of sialoadenectomy on LPS/GalN-induced liver toxicity may be the consequence of an altered cytokine production by the liver and a reduced CS release from adrenal glands.