Cetyl Myristoleate Isolated from Swiss Albino Mice: An Apparent Protective Agent against Adjuvant Arthritis in Rats

Concerning the anti-arthritic action of cetyl myristoleate in rats: An interim report

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The proposed arthro-preventive action of cetyl myristoleate, an OTC product sold as a nutritional supplement, could not be confirmed, using an almost identical bioassay (adjuvant-induced polyarthritis in rats) as that described in the original report (Diehl and May, 1994) with the same, and 3 other, dosing schedules.

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“…(i) as a single dose dissolved in oil and injected s.c. 48 h before the arthritigen, the procedure described by Diehl and May (1994); (ii) prophylactically as an aqueous dispersion or olive oil solution given orally for 16 days beginning on the day before the arthritigen was injected; (iii) therapeutically given s.c. only after the first signs of arthritis were manifest (day 10) for 4 days only; (iv) co-administration with the arthritigen.…”

“…(Arthritigenic adjuvants based on poorly metabolised mineral oil are proscribed by our Animal Ethics Committee.) Table 1 shows data from attempts to repeat the original observation that CMO might be arthro-protective (Diehl and May, 1994). Pure synthetic CMO was given at 75 mg/rat, the dose indicated, in both light mineral oil (as indicated) and in olive oil (less tissue-irritant) to female Wistar and DA rats prior to the arthritigenic adjuvant.…”

“…The original bioassay for CMO (Diehl and May, 1994) used male Sprague-Dawley rats (bred in Chicago) and a mineral oil adjuvant to induce the polyarthritis. Locally available Sprague-Dawley rats (University of Queensland Medical School) did not develop a readily quantifiable polyarthritis when injected in the tail base with a metabolisable arthritigenic adjuvant (Mycobacterium tuberculosis in squalane).…”

“…In 1994, an astonishing report was published (Diehl and May, 1994) supposedly resolving the paradox that rats, but not mice, develop an auto-allergic polyarthritis after injecting a Freund's adjuvant (oil and mycobacterium) alone, i.e. without any co-administered auto-antigen.…”