Histological analysis on rat superficial cervical lymph node

Superficial cervical lymph nodes (SCLN) are important for the defense mechanism against oral diseases. The anatomical nad ontogenical appearance of rat SCLN were examined histologically or immunohistologically. Thefollowing evidences were proved. (1) Generally, there were 4 pairs of SCLN. However some nodes were defective. Thus, according to the numbers of nodes, SCLN were classified to 5 types. Among the 4 nodes, No.2 nde was the most inportant one in the oral diseases. (2) Ontogenically, SCLN showed typical features of mature structure since 3 weeks after birth. (3) The histological changes of SCLN were analysed when the lower lip was stimulated with OK432. The increased number of germinal center and cell number of T cell areas were observed. Besides these HEV endothlium showed vacuolation. (4) The histological changes of SCLN were also examined when rat squamous cell carinoma was transplanted into the lower lip. Increased weight of SCLN was observed and several shanges of the lympth nodes including vacuolation of HEV endothelium was observed. These results were considered from the view point of the defense mechanism of SCLN against oral diseases.