engleski

The effects of pharmacological pinealectomy on the regenerating liver and lymphoid morphostasis of hepatectomized rats

To determine wheather pharmacological pinealectomy (PX) influences regenerative growth of the liver and lymphoid morphostasis, partially hepatectomized (PHx) rats were treated in the morning or in the evening with propranolol (PRO ; 30 mg/kg s.c.) or with the same amount of saline. A group of HX and PX rats was also treated with evening injections of melatonin (10 mg/kg i.p.). The data show that pharmacological PX supresses the early increase of DNA (at 24h) and bromodeoxyuridine (BrdU)index in regenerating liver from the first to the seventh post-operative day. Simultaneously, an inhibitory effect on pHX-induced class II antigen expression in regeneratiing liver was noticed, which persisted until the last day of examination (seventh day), and was not correctable by the evening injections of melatonin. Pharmacological PX was followed by marked changes in the lymphatic morphostasis in the spleen (early increase of CD8+, IL-2R+ and B cells ; decrease of Mac-1+ and Mac-3+ cells, followed by an increase of Mac-1+ in the latter phases of liver regeneration).HX-induced changes were additionally affected by exogenous melatonin.It increased the proportion of W3/25+ cells in both PX and non-PX rats, but its effects on other cells were not the same in PX and non-PX rats (increase of IL-2R+ and Mac-1+ cells, and decrease of B cells in the former, and increase of B and MAC-3+ cells, and decrease of OX-42+ cells in the latter), suggesting the involvement of different mediators for observed changes. Sympathectomy performed in the morning also produced some changes in the spleen, but the effects which were visible only after the evening injection of PRO suggest that the pineal gland is involved in the control of lymphatic morphostasis and compensatory liver growth.

partial hepatectomy, liver regeneration; propranolol, melatonin, expression of class II antigens in liver; spleen cell phenotype

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