EFFECT OF INTRA PERITONEAL INJECTION OF HISTIDINE ON COLD ALLODYNIA, FORMALIN PAIN TEST AND PATHOLOGY OF CRUSHED SCIATIC NERVE IN RAT

Protective effect of histidine on nervous system is well studied. We aimed to
evaluate the efficiency of cold allodynia and formalin pain tests with pathology in histidine injection
as intra peritoneal method in rat’s crushed sciatic nerve.
Materials & Methods: 57 rats were used for evaluating cold allodynia and formalin pain tests.
Histopathological sections were stained with two staining methods. Numbers of schwann cells and
myelinated nerve fibers were evaluated for repair processing.
Results: Cold allodynia and formalin pain tests in histidine 400mg/kg group had the best results and
most likeness with pathology. In this group, cold allodynia was started on the 7th day after lesion
creation in sciatic nerve and achieved to maximum on the 14th and 28th days and then decreased till the
end of the experiment (42nd day) and compared with the control group (p<0.05). Also formalin pain
response decreased on 14th, 28th and 42nd days compared with before lesion creation according to the
control group (p<0.05).
Conclusion: Results of the current study showed that cold allodynia and formalin pain tests with
pathology confirmed effect of histidine 400mg/kg on repair of crushed sciatic nerve. Also results of
this and previous studies showed that physiological tests for neuropathic pain, function index, cold
allodynia and formalin pain have more efficiency with pathological results, respectively