TY - JOUR
T1 - Role of protein kinase C in estrogen protection against apoptotic cerebellar cell death in ethanol-withdrawn rats
AU - Jung, Marianna E.
AU - Watson, David G.
AU - Wen, Yi
AU - Simpkins, James W.
N1 - Funding Information:
This work was supported by the Pharmacology & Neuroscience Department at the University of North Texas Health Science Center at Fort Worth.
PY - 2003
Y1 - 2003
N2 - Results of studies from our laboratory have shown that administration of 17β-estradiol (E2) reduces cerebellar neuronal damage during ethanol withdrawal (EW). In the current study, we examined mechanisms underlying E2 protection against EW-associated cerebellar damage by assessing apoptotic indicators: DNA fragmentation, caspase-3 activity, and protein kinase C (PKC) activity. Ovariectomized rats, implanted with E 2 or oil pellets, received ethanol [7.5% weight/volume (wt./vol.)] (EW/E2 group and EW/Oil group, respectively) chronically (for 5 weeks) or control dextrin diet (Dextrin/Oil group). At day 14 of EW, cerebelli were collected for the terminal deoxynucleotidyltransferase (TdT)-mediated dUDP-biotin nick end labeling (TUNEL) assay to detect DNA fragmentation and for immunohistochemistry to detect caspase-3 activation. A separate group of rat cerebelli was prepared to assess for total PKC activity, as well as for activity of a specific PKC isozyme, epsilon (PKCε), by using an in vitro [γ-32P]ATP phosphorylation assay at days 1 and 14 of EW. Results indicated that rats in the EW/Oil group had more DNA fragments and caspase-3-positive neuronal cells than observed for control rats, and these effects were inhibited by E2 treatment. For total PKC activity at day 1 of EW, rats in the EW/E2 group had a lower cytosolic PKC activity than observed for either rats in the EW/Oil group or control rats. At day 14 of EW, both EW groups had a lower total PKC activity than observed for control rats. For PKCε activity, rats in the EW/E2 group had a lower cytosolic PKCε activity than observed for rats in the EW/Oil group or for control rats at day 1, and they had a lower membrane PKCε activity at day 14 of EW than observed for control rats. These findings support the suggestion that E2 protects against cerebellar neuronal damage in ethanol-withdrawn rats by inhibition of DNA fragmentation and caspase-3 activation, and that reduced PKC activity may be involved in the protection.
AB - Results of studies from our laboratory have shown that administration of 17β-estradiol (E2) reduces cerebellar neuronal damage during ethanol withdrawal (EW). In the current study, we examined mechanisms underlying E2 protection against EW-associated cerebellar damage by assessing apoptotic indicators: DNA fragmentation, caspase-3 activity, and protein kinase C (PKC) activity. Ovariectomized rats, implanted with E 2 or oil pellets, received ethanol [7.5% weight/volume (wt./vol.)] (EW/E2 group and EW/Oil group, respectively) chronically (for 5 weeks) or control dextrin diet (Dextrin/Oil group). At day 14 of EW, cerebelli were collected for the terminal deoxynucleotidyltransferase (TdT)-mediated dUDP-biotin nick end labeling (TUNEL) assay to detect DNA fragmentation and for immunohistochemistry to detect caspase-3 activation. A separate group of rat cerebelli was prepared to assess for total PKC activity, as well as for activity of a specific PKC isozyme, epsilon (PKCε), by using an in vitro [γ-32P]ATP phosphorylation assay at days 1 and 14 of EW. Results indicated that rats in the EW/Oil group had more DNA fragments and caspase-3-positive neuronal cells than observed for control rats, and these effects were inhibited by E2 treatment. For total PKC activity at day 1 of EW, rats in the EW/E2 group had a lower cytosolic PKC activity than observed for either rats in the EW/Oil group or control rats. At day 14 of EW, both EW groups had a lower total PKC activity than observed for control rats. For PKCε activity, rats in the EW/E2 group had a lower cytosolic PKCε activity than observed for rats in the EW/Oil group or for control rats at day 1, and they had a lower membrane PKCε activity at day 14 of EW than observed for control rats. These findings support the suggestion that E2 protects against cerebellar neuronal damage in ethanol-withdrawn rats by inhibition of DNA fragmentation and caspase-3 activation, and that reduced PKC activity may be involved in the protection.
KW - 17β-estradiol
KW - Apoptosis
KW - Ethanol withdrawal
KW - PKCε
KW - Rats
UR - http://www.scopus.com/inward/record.url?scp=0242407618&partnerID=8YFLogxK
U2 - 10.1016/j.alcohol.2003.07.004
DO - 10.1016/j.alcohol.2003.07.004
M3 - Article
C2 - 14615010
AN - SCOPUS:0242407618
SN - 0741-8329
VL - 31
SP - 39
EP - 48
JO - Alcohol
JF - Alcohol
IS - 1-2
ER -