الفهرس 
Materials and methodsOnly 14 pages are availabe for public view
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Abstract
The present study was conducted on 120 male rabbits to probe
the effect of dexamethasone and loratadine administration in the
dose of 0.09mg/lOO gm of rabbit’s body weight/day orally in the
syrup form for two weeks on the structure of the mesenteric lymph
nodes and the bone marrow lymphocytes in 3 different ages.
The animals were classified _into 3 different age groups;
namely, group I (young age of 4 weeks), group II (adult age of9
months), and group III (old age on years). Each group was formed
of40 male rabbits and subdivided into other 3 subgroups.
• Subgroup A was the control subgroup formed of 10 rabbits
that were administered distilled water.
• Subgroup B was the dexamethasone subgroup formed of 15
rabbits that were administered dexamethasone.
Subgroup C was the loratadine subgroup formed of 15 rabbits
that were administered loratadine.
Histological sections were stained with H & E to study the
general structure of the mesenteric lymph nodes and to measure the
size of the lymphoid follicles and their germinal centers which are
indicators of the activity of lymph node and their lymphocyte
proliferation.
Also bone marrow smears were stained with Giemsa stain to
determine the percentage of transformed lymphocytes in the bone
marrow which were considered as an indicator of the degree of
lymphocyte proliferation.
The results of the present study revealed the following:
1-The dexamethasone reduced the size of lymphoidfollicles and
their germinal centers to a highly significant degree (P < 0.005)
and decreased the percentage of transformed lymphocytes in the
bone marrow to a highly significant degree when compared with
the control subgroup of the same age at the different age groups.
2- The loratadine did not affect the size of lymphoid follicles or their
germinal centers, and did not decrease the percentage of
transformed Imphocytes in the bone marrow when compared with
the control subgroup of the same age at the different age groups.
3- There was a highly significant difference (P < 0.005) between the
different age groups in the control, dexamethasone and loratadine
subgroups due to the effect of aging and not due to the
administered drugs.
The present study may provide an evidence that it is better to
use loratadine in treatment of chronic allergic diseases because it has
no effect on the immune system. In contrast, dexamethasone caused
a highly significant depression to the immune system when used for
long periods at the different age groups.