Increased apoptosis of bone marrow pre-B cells in old mice associated with their low number.
The number of bone marrow pre-B cells is significantly lower in 18- than in 2-month-old BALB/c mice. The percentage of apoptotic pre-B cells, freshly isolated or cultured, from 18-month-old mice was significantly greater than from 2-month-old mice. The increased percentage of apoptotic pre-B cells from old mice was associated with a decreased level of bcl-xL mRNA, detected by RT-PCR, and of Bcl-xL protein, detected by intracellular staining. Consistent with an age-associated increase in apoptosis in pre-B cells was the fact that significantly fewer pre-B cells were generated after in vitro cultures of pro-B cells from old as compared to young mice. Furthermore, fewer pre-B cells survived and fewer sIg-expressing B cells were generated in cultures of pre-B cells from old as compared to young mice. In addition, there was no detectable difference in the secretion of IL-7 by bone marrow cells from 2- or 18-month-old mice. Thus, increased apoptosis of bone marrow pre-B cells in old mice appears to contribute to their decreased number.
Kirman
I
I
Division of Geriatrics and Gerontology, Cornell University Medical College, New York, NY 10021, USA.
Zhao
K
K
Wang
Y
Y
Szabo
P
P
Telford
W
W
Weksler
M E
ME
D000375:Aging / Q000502:physiology*; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001402:B-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism; D005260:Female; D015851:Interleukin-7 / Q000096:biosynthesis / Q000378:metabolism; D018655:Lymphocyte Count; D051379:Mice; D008807:Mice, Inbred BALB C; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051020:bcl-X Protein
C494812:Bcl2l1 protein, mouse; D015851:Interleukin-7; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051020:bcl-X Protein