Tissue microarrays in pathological examination of apoptotic acinar cells induced by dexamethasone in the pancreas of rats with severe acute pancreatitis.
BACKGROUND
The good therapeutic effects of large dose of dexamethasone on severe acute pancreatitis (SAP) patients have been proved. This study was designed to investigate the influence of dexamethasone on apoptosis of acinar cells in the pancreas of rats with SAP and the protein expression of the apoptosis-regulating genes Bax and Bcl-2.


METHODS
Ninety Sprague-Dawley rats with SAP were randomly divided into a model group and a dexamethasone treated group (45 rats in each group), and another 45 rats formed the sham operation group. Survival rates were calculated and gross pathological changes in the pancreas of each group were observed under a light microscope 3, 6 and 12 hours after operation. Tissue microarray technology was applied to prepare pancreatic tissue sections. The changes in Bax and Bcl-2 protein expression levels of pancreatic tissues from each group were assessed by immunohistochemical staining, and TUNEL staining was used to evaluate changes in apoptosis index.


RESULTS
The model and treated groups did not differ in mortality at each time point. The pathological score for the pancreas in the treated group was significantly lower than that in the model group at 3 and 6 hours. The positive rates of Bax protein expression in the head and tail of the pancreas in the treated group at all time points were all markedly higher than those of the model group. The positive rate of Bcl-2 protein expression in the head of the pancreas in the treated group was significantly higher than that of the model group at 3 hours. TUNEL staining showed that the pancreas head and tail apoptosis indices of the treated group were markedly higher than those of the model group after 6 hours.


CONCLUSIONS
Apoptosis may be a protective response to pancreatic cell injury. The mechanism of action of dexamethasone in treating SAP may be related to the apoptosis of acinar cells in the pancreas induced by apoptosis-regulating genes such as Bax and Bcl-2. The advantages of tissue microarrays in pathological examination of the pancreas include saving of time and energy, efficiency and highly representative.
Zhang
Xi-Ping
XP
Department of General Surgery, Hangzhou First People's Hospital, Hangzhou 310006, China. zxp99688@vip.163.com
Tian
Hua
H
Lu
Bei
B
Chen
Li
L
Xu
Ru-Jun
RJ
Wang
Ke-Yi
KY
Wang
Zhi-Wei
ZW
Cheng
Qi-Hui
QH
Shen
Hai-Ping
HP
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D004247:DNA / Q000235:genetics; D003907:Dexamethasone / Q000008:administration & dosage / Q000627:therapeutic use*; D004195:Disease Models, Animal; D015870:Gene Expression / Q000187:drug effects; D005938:Glucocorticoids / Q000008:administration & dosage / Q000627:therapeutic use*; D020287:In Situ Nick-End Labeling; D008297:Male; D019283:Pancreatitis, Acute Necrotizing / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D012720:Severity of Illness Index; D046888:Tissue Array Analysis / Q000379:methods*; D016896:Treatment Outcome; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis / Q000235:genetics
C494828:Bax protein, rat; D005938:Glucocorticoids; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D003907:Dexamethasone; D004247:DNA