EXPERIMENTAL STUDY ON EFFECTS OF YANG YIN
INJECTION ON THYMOCYTES APOPTOSIS INDUCD BY DEXAMETHASONE IN INFANCY RATS
Wang Jun, Tong Xiaolin, Wang
Kun, Yang Menglan
Department of Pediatrics,
China-Japan Friendship Hospital, Beijing, China
Objective: Apoptosis is a programmed cell death
under the pathological and physiological conditions. Many experimental
study indicated that glucocorticoid could induce thymocyte apoptosis, which
result in atrophy of thymus. This might be one of the mechanisms of immunological
function defect induced clinically by glucocorticoids. The study on the
control of disease by regulating apoptosis is one of the hot points recently.
Our previous study showed that protection of red blood cell and liver cell
by Yang Yin Injection was observed. This report is focused on the research
of inhibition of apoptosis in infancy rats by Yang Yin Injection (traditional
Chinese medicine) on the basis of successful apoptotic model induced by
dexamethasone.
Methods: 30 infancy rats (4～5-week-old) were divided into three groups
randomly. ①The control group : Introperitoneal
injection of Saline , once a day for 5 days ; ②The Yang Yin Injection group: After
Introperitoneal injection of Yang Yin Injection for five days ,
Introperitoneal injection of Dexamethasone (0.02g/kg) on 5 PM of the day ; ③ Dexamethasone group: Introperitoneal injection of
Dexamethasone (0.02g/kg) at the same time as Yang Yin Injection group. All
the animals of three groups were killed at the same time (8 AM of the 6th
day). The apoptosis of thymocyte was studied and analyzed by morphology,
TUNEL (terminal-deoxynucleotidyl transferase mediated d-UTP nick end
labeling), DNA agarose gel electrophoresis and flow cytometry etc.
Results: Apoptotic cell labelled by TUNEL, thymocytes
in dexamethasone group was stained markedly with strong fluorescent light
under the fluorescent microscope which was locally distributed; the
thymocytes in Yang Yin Injection group was scatteredly. Under the light
microscope , The number of TUNEL positive thymocytes in dexamethasone group (Apoptosis
Index was 0.41±0.01) was much higher than that in Yin
Injection group(Apoptosis Index was 0.07±0.004).
The results showed it had significant difference between these two groups
(P<0.01). Agarose gel electrophoresis showed typical DNA ladder in
dexamethasone group, but there was only weak ladder in Yang Yin Injection
group. Results of flow cytometry showed typical apoptosis peak in
dexamethasone group (apoptosis percentage was 60.74±4.86%), but Yang Yin Injection group's was weak
(apoptosis percentage was 32.20±7.70%).There
was a significant difference between the two groups (P<0.01). Under the
electron microscope, the morphology of thymocytes in Yang Yin Injection
group was almost no change. The distribution of chromatin was normal.
Conclusions: Yang Yin Injection could reduce
apoptosis induced by dexamethasone. Yang Yin Injection might inhibit
glucocorticoid-induced thymocyte apoptosis. It means Yang Yin Injection
could protect thymus from the cell injury to some extent, which helps
treatment of children's nephrotic syndrome.