Background & Aims: 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 7^th day after lesion creation in sciatic nerve and achieved to maximum on the 14^th and 28^th days and then decreased till the end of the experiment (42^nd  day) and compared with the control group (p<0.05). Also formalin pain response decreased on 14^th, 28^th and 42^nd 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. 

SOURCE: URMIA MED J 2015: 26(6): 541 ISSN: 1027-3727