[The increase of protein synthesis by zinc can resist the damage induced by streptozotocin on islet cells].
The beneficial effect of ZnCl2 on islet cells injured by streptozotocin was observed directly on the cultured cells and its possible mechanism was analysed. The results were as follows: (1) The number of viable cells in culture was reduced from 70 x 10(5)/ml to 43.93 +/- 1.16 x 10(5)/ml 12 hours after adding normal saline plus STZ (3.0 mmol/L), and this reduction could be alleviated by adding ZnCl2 (0.25, 0.5, 1.0 mmol/L) in varying amounts and a dose-response relationship was found. The number of viable cells was returned to 47.39 +/- 0.88 x 10(5)/ml, 58.06 +/- 2.29 x 10(5)/ml, and 67.72 +/- 1.48 x 10(5)/ml respectively in the culture with ZnCl2 of different levels. (2) The effect of ZnCl2 was reversed when cycloheximide (100 micrograms/ml), a protein synthesis inhibitor, was added into the cultural medium, and the number of viable cells was again decreased from 63.17 +/- 2.15 x 10(5)/ml to 45.77 +/- 0.76 x 10(5) ml. No obvious effect was observed when cycloheximide was given alone. (3) The experiment of 3H-leucine incorporation into islet cells showed that protein synthesis was increased slightly and insignificantly after adding ZnCl2 (1.0 mmol/L). However, there was a significant increase of protein synthesis in cells when ZnCl2 (1.0 mmol/L) was added with STZ (3.0 mmol/L). The results suggest that ZnCl2 has a protective effect on the damaged islet cells induced by STZ. The increase of protein synthesis may be one of the mechanisms involved in the action of ZnCl2, which strengthens the repairing ability of islet cells after injury.
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D000818:Animals; D002478:Cells, Cultured; D002712:Chlorides / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects*; D014176:Protein Biosynthesis; D051381:Rats; D013311:Streptozocin; D015032:Zinc / Q000494:pharmacology*; D017967:Zinc Compounds
D002712:Chlorides; D017967:Zinc Compounds; D013311:Streptozocin; C016837:zinc chloride; D015032:Zinc