Expression of tumor necrosis factor-alpha converting enzyme in liver regeneration after partial hepatectomy

To study the expression of tumor necrosis factor-alpha converting enzyme (TACE) and evaluate its significance in liver regeneration after partial hepatectomy in vivo.

Male SD rats underwent 70% partial hepatectomy. The remaining liver and spleen tissue samples were collected at indicated time points after hepatectomy. TACE expression was investigated by Western blotting, immunohistochemistry, and serial section immunostaining.

Expression of TACE in liver and spleen tissues after partial hepatectomy was a time-dependent alteration, reaching a maximal level between 24 and 48 h and remaining elevated for more than 168 h. TACE protein was localized to mononuclear cells (MNC), which infiltrated the liver from the spleen after hepatectomy. The kinetics of TACE expression was in accordance with the number of TACE-staining MNCs and synchronized with those of transforming growth factor-alpha (TGFalpha). In addition, TACE-staining MNC partially overlapped with CD3+ T lymphocytes.

TACE may be involved in liver regeneration by pathway mediated with TGFalpha-EGFR in the cell-cycle progressive phase in vivo. TACE production and effect by paracrine may be a pathway of involvement in liver regeneration for the activated CD3+ T lymphocytes.