Abstract:
Anaemia is one of the most clinically encountered conditions in animals and humans. It
continues to be a global public health problem, affecting both developing and developed
countries with major consequences for human and animal health as well as social and
economic development. The objective of this study was to develop and test a rat model for
experimental studies on sub-acute blood loss anaemia. The study design was an
experimental research and development protocol, made up of two experiments (1 and 2).
Experiment 1 was for development of the model while experiment 2 was for testing the
developed model. A total of 162 albino rats of either sexes, between the ages of 10 and 12
weeks weighing 130 – 250g were used for the study. In experiment 1, 130 rats were
assigned at random, into thirteen groups of ten each (5 males & 5 females) labeled 1 to 13.
Baseline values of the haematological parameters and serum protein were determined using
standard procedures before the commencement of the study. Rats in group 1 were not bled
and served as control. Blood loss was induced at specified periods of time for the remaining
12 groups using the orbital bleeding technique. At the end of the specified period of
bleeding for each group, the haematological parameters and serum protein were re-assessed
in order to select which group met the target of halving the RBC count, Hb and packed cell
volume (PCV) with minimal stress, which is characteristic of sub-acute blood loss anaemia.
In experiment 2, the selected group was tested using varied haematinics in 32 rats assigned
at random into four groups labeled A to D: group A was the non-anaemic control, group B
was the selected model treated with ferrous sulphate + folic acid + vitamin B-complex daily
for 7 days, group C was the selected model treated with HB12® (haemoglobin syrup and
vitamin B12) daily for 7 days and group D was the selected model not treated with
haematinics. Data generated from all parameters assessed for each of the groups were
compared using a one way analyses of variance, and variant means were separated using the
least significant difference. Results obtained pre and post-bleeding in experiment 1 were
subjected to t-test for paired samples. Significant difference was accepted at p < 0.05. The
PCV, Hb, RBC counts of the rat groups that were bled (groups 2 – 13) decreased
significantly (p < 0.05) after bleeding to varying degrees across the groups based on the
volume of blood removed and the duration, except in the males of group 2 and 3 and
females of group 9. The greatest percentage decrease in overall PCV, Hb and RBC counts
was recorded in group 12 (42.4% for PCV, 48.1% for Hb and 44.4% for RBC count) and
males in the group had significantly (p < 0.05) greater decreases than females. There was no
significant changes (p > 0.05) in the PCV, Hb and RBC count of the unbled control group
(group 1). The reticulocyte count of all the rat groups that were bled (groups 2-13)
significantly (p < 0.05) increased after bleeding, with the rat groups bled daily having the
highest increases. There were no significant (p > 0.05) changes in the reticulocyte count of
the group 1 rats. The serum total proteins of rats in groups 9 and 13 were significantly
higher (p < 0.05) after bleeding but those for rats in groups 5, 6 and 11 were significantly
lower (p < 0.05) after bleeding. No significant changes (p > 0.05) were recorded in the
serum total proteins of rats in groups 1, 2, 3, 4, 7, 8 and 12. The total white blood cell
(WBC) counts of rats in groups 2, 3, 4, 7, 8, 9, 10 and 13 were significantly (p < 0.05)
reduced after bleeding, but that of rats in groups 1, 5, 6, 11 and 12 did not significantly (p >
0.05) change. Rats in group 12 bled 2 ml/100 g b.w. every other day for 20 days topped all
other groups in meeting the target of halving the PCV, Hb and RBC with minimal stress and
were selected as the model for further testing in experiment 2. In experiment 2, the rats
rendered anaemic by bleeding 2 ml/100 g b.w. every other day for 20 days and treated with
two haematinics responded to treatment by normalization of their PCV, Hb, RBC and
reticulocytes 6 – 9 days post-treatment. It was concluded that removal of 2 ml of
blood/100g b.w. from 10 – 12 weeks old rats every other day for 20 days is recommended
for the induction of sub-acute blood loss anaemia in rats.