Apoptosis induced by zinc deficiency in rat osteoblast: possible involvement of protein kinase C.
Rat osteoblasts were isolated from the 21-day fetal rat calvarias. The cells were grown in DMEM plus 10% FBS, and were treated for 24 h. with 10 mumol/L TPEN or 10 mumol/L TPEN supplemented with 10 mumol/L Zn2+. Apoptosis of osteoblasts were measured by flow cytometry, electron microscopy and DNA fragmentation analyzed by gel electrophoresis. In addition, IP3 production and PKC activity were measured in order to show whether they are involved in apoptosis in osteoblast induced by zinc deficiency. The results showed that 10 mumol/L TPEN could induce apoptosis in osteoblast in 24 h. But cells treated with 10 mumol/L TPEN supplemented with 10 mumol/L Zn2+ showed no apoptotic changes in 24 h. TPEN significantly reduced the formation of IP3 and PKC activity after 24 h incubation. No differences were observed between the cells treated with TPEN supplemented with Zn2+ simultaneously and the untreated cells. It can be inferred that apoptosis induced by zinc deficiency may be due to the decreased activity of PKC which is impaired by reduced formation of IP3.
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Medical Experimental Center, First Hospital of West China University of Medical Sciences, Chengdu, China.
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Wang
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D000818:Animals; D017209:Apoptosis; D002454:Cell Differentiation; D005314:Embryonic and Fetal Development; D010006:Osteoblasts / Q000187:drug effects / Q000502:physiology*; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D015032:Zinc / Q000172:deficiency*
D011493:Protein Kinase C; D015032:Zinc