Complete Freund’s Adjuvant, 1 mg/ml

1956, Pearson determined that rats immunized with Complete Freund’s Adjuvant (CFA), mineral oil containing heat-killed Mycobacterium tuberculosis (MT) debris, evolved polyarthritis. This arthritis version, known as Adjuvant-Induced Arthritis (AIA), has formerly been used as a version for rheumatoid arthritis (RA). However, AIA is a extra suitable version for reactive arthritis in preference to RA, because of the variations in histological and immunological features (1, 2) Chondrex, Inc. offers CFA containing diverse concentrations of MT for inducing AIA. However, CFA containing 1 mg/ml MT is seldom powerful for inducing AIA.

For powerful induction, CFA containing 10 mg/ml MT is recommended, despite the fact that CFA containing five mg/ml of MT is likewise able to inducing AIA. AIA can without problems be triggered in prone lines of rats with the aid of using a unmarried subcutaneous injection of CFA (zero.05-zero.1 ml) containing 10 mg/ml MT (Catalog #7027) right into a footpad or at the bottom of the tail. Before every injection, it’s far important to re-droop the adjuvant because the mycobacterial debris will settle. Failure to re-droop the adjuvant ought to cause inconsistent distribution of mycobacterial debris.

Choose footpad or base of the tail injection relying at the cause of the study.

1) Footpad injection

Subcutaneously inject zero.05 ml of CFA containing 10 mg/ml MT into the footpad of a rear paw. Severe and acute irritation could be discovered inside half-hour of the injection. The irritation peaks inside three-four days and lasts for 20-25 days. Secondary arthritis withinside the non-injected paws commonly seems inside 12-14 days of the injection. The arthritis peaks inside 2-three days of its onset and lasts for 20 to twenty-five days.

2) Base of the tail injection

• Inject zero.1 ml of CFA containing 10 mg/ml MT subcutaneously at the bottom of the tail.
• Arthritis will seem in a single or all paws among 12-14 days after the injection and closing for 20 to twenty-five days AIA become triggered in SD rats with the aid of using injecting zero.05 ml CFA (10 mg/ml MT) withinside the proper hind paw footpad on Day zero.
• Severe irritation withinside the paw evolved at once after injection. Secondary arthritis evolved withinside the left hind paw footpad on day 12-14 after injection.
• The impact of the anti inflammatory take a look at compound become decided with the aid of using evaluating footpad volumes in handled and untreated rats.

Note 1: It isn’t important to apply an emulsified adjuvant to set off AIA. However, to keep away from inconsistent dosage of M. tuberculosis, CFA containing 20 mg/ml MT (Catalog # 7024) may be emulsified with an identical quantity of saline or buffer answer and used for sensitization. This approach has been said for inducing AIA in F344 rats with mycobacterial peptidoglycans and muramyl dipeptides (three).

Note 2: Particle sizes of M. tuberculosis powder influences AIA development (four). Chondrex, Inc.’s MT powder is floor drastically earlier than CFA preparation. This step will increase prevalence and consistency of severity of AIA in lots of rat lines. Clinical Arthritis Scores The severity of arthritis may be scored with the aid of using visible inspection. Chondrex, Inc. recommends scoring arthritis on a scale of zero to four in every paw. The tail base injection approach ratings arthritis in all 4 paws , even as the footpad injection approach ratings arthritis in 3 paws, with the exception of the adjuvant-injected paw .

Paw Thickness and Volume Assessment

Foot swelling  related to arthritis severity may be objectively decided with the aid of using measuring paw thickness and quantity. Paw thickness may be measured the use of a caliper consisting of the Mitsutoyo loop-take care of dial thickness gauge, even as paw quantity may be measured the use of a plethysmograph.  pattern facts of comparing anti inflammatory dealers with the aid of using measuring paw quantity.

Environmental elements also are vital for inducing AIA. Housing situations can have an effect on the microbial composition of experimental animals, which in flip can have an effect on ailment phenotypes (7). To decrease this variation, Chondrex, Inc. recommends housing rats in SPF situations each time possible. However, if SPF housing situations aren’t possible, we endorse very well cleansing your housing facility earlier than receiving the rats and at some stage in the experiment.