Gap junction protein connexin 43 and its distribution in damaged nerve cells

BACKGROUND: Connexins, particularly connexin 43, form gap junctions that mediate neuron-glial communication. To date, the expression of connexin 43 in phenotypically distinct neurolemmocytes, in particular non-myelinating (Remak cells) and repair Schwann cells, has not been studied. AIM: To determine the presence of connexin 43 in Schwann cells of the rat sciatic nerve under normal conditions and after mechanical damage by applying a ligature. MATERIALS AND METHODS: The study was carried out on Wistar rats (n = 10). In experimental rats, the sciatic nerve was damaged by applying a ligature (40 s). 7 days after surgery, sciatic nerve segments were isolated for subsequent immunohistochemical study using antibodies to connexin 43 and glial fibrillary acidic protein (GFAP). In the control group rats, segments of intact sciatic nerves were isolated in a similar way. RESULTS: It has been shown that in the endoneurium of the intact rat sciatic nerve there are no cells expressing connexin 43. It was found that 7 days after injury, a large number of connexin-43-immunopositive cells of irregular shape with several processes were identified in the endoneurium of the damaged nerve. There was a lack of expression of connexin 43 in GFAP-containing Schwann cells. CONCLUSIONS: It can be stated that nerve damage leads to active synthesis of the studied protein by endoneurium cells; however, the origin of the cells expressing connexin 43 remains to be elucidated.