Applicability of the Popliteal Lymph Node Assay in the Brown-Norway Rat

Abstract

A number of drugs and chemicals can induce autoimmune disorders. Previous studies suggested the popliteal lymph node (PLN) assay might be a suitable and reliable model to detect such compounds in the mouse. the applicability of this assay has been examined in the Brown-Norway rat using a pannel of positive as well as negative reference compounds.

Popliteal lymph nodes were excised and weighed seven days after subcutaneous injection of 5 mg of each compound into one footpad. Interestingly, all negative reference compounds produced no significant increase in PLN weight index whereas four positive reference compounds were associated with PLN-weight indices greater than 2.3.

However, no increase in PLN weight was noted in procainamide-and isoniazide-treated rats as previously reported in the mouse. This first set of experiments indicates that the PLN assay is applicable to Brown-Norway rats and warrants further investigation.