There are different techniques depending upon the types of tissue samples used for immunohistochemistry. As you mentioned only about rat sample, any tissue samples can be processed for immunohistological techniques. But you should be confirmed about the type of antibody to be used, the methods of antigen retrieval, blocking and the concentration of antibody needed, buffer needed for washing purpose, before you proceed. For your information wax embedded histological sections need antigen retrieval while most of the frozen histological section do not need. For visualization of the antibody binding you may use DAB chromogen if you are using HRP or you may use Fluorescence detection techniques if you are using Fluorescent secondary antibodies. I strongly recommend you to optimize the antibody concentration, color detection and antigen retrieval methods before you proceed for the good sections for immunohistochemistry.

Hello Lokesh. Immunohistochemistry technique is specified to detect protein antigen in tissue. So you have to specify the tissue you are going to study and the exact protein that you are investigating. The important issue that you have to be sure that the primary antibody must be anti-rat antibody to react with corresponding tissue antigens in in rats. Good luck