The number of lung cancer patients is increasing. One complication of particular concern after surgery for lung cancer is postoperative pneumonia. The present study examined the various effects of oral care cough reflexes (cough reflex test), oral health conditions (OAG and face scale), and immune function (NK cell activity) in patients who underwent surgery for lung cancer.

  Subjects included 60 patients aged 75 years old or younger who were scheduled to undergo surgery for stage Ⅰ lung cancer. The average age was 65.3±6.0 years old. We randomly divided the subjects into an oral care group and a control group.

  In the oral care group, we observed a significant increase in the normal rate of cough reflex test post-surgery, relative to pre-surgery. In contrast, no significant change in the normal rate of cough reflex test was noted for patients in the control group. Oral health conditions showed similar results. While we observed no significant change in NK cell activity from between pre-surgery and post-surgery in the oral care group, we did note a significant decrease in the control group. Two cases of pneumonia after surgery were identified in the control group. The oral care group did not get postoperative pneumonia. Thus, it was shown that oral care is related to cough reflex, oral health conditions, and immune function.

  It has been reported that hyaluronan tetrasaccharide (HA4) has an ability to accelerate the healing process of spinal cord injuries and to mitigate the symptoms of experimental autoimmune encephalitis (EAE) in animal models. However, the precise mechanisms of the effect of HA4 are unclear.

  This study examined the in vitro effects of HA4 on the differentiation of PC12 cells and neuronal progenitor cells from mouse embryo. The effect of HA4 on the proliferation and differentiation of rat oligodendrocyte precursor cells was examined.

  HA4 upregulated neurite-outgrowth of cultured PC12 cells in the presence of Nerve Growth Factor (NGF), which induces neuronal differentiation in PC12. HA4 also upregulated βⅢ-tubulin positive cells and increased the expression of neurofilament M, two of the marker proteins of nerve differentiation. The activation was observed in an HA4 dose-dependent manner, and the effect was observed at levels as low as femtogram/L. Furthermore, the enhancement of neurite-outgrowth was not observed in the presence of hyaluronan disaccharide, hexasaccharide, 12 mer or high molecular weight hyaluronan. Upregulation of neurite-outgrowth was observed only in the presence of NGF.

  While HA4 accelerated neurite-outgrowth of primary mouse neural progenitor cells, it did not enhance the proliferation or differentiation of oligodendrocyte precursor cells derived from rat primary neuronal progenitor cells in culture.

  These results suggest that the effects of HA4 alleviating some neuronal diseases may be ascribable, at least in part, to its capacity to enhance differentiation of neurons.