Table 2 Peripheral mechanisms of knee OA

Cairns et al., 2001 [27]

Rat

Rat

Glutamate injected into masseter muscle produced greater nociceptor excitation in female rats.

Cook and Nickerson, 2005 [31]

Rat

Rat

Mu-opioid agonists are more effective in male vs. female arthritic rats; effects are both peripheral and central.

Flake et al., 2005 [26]

Rat

Compared ovariectomized with and without estrogen; Estrogen increases nociceptor excitability of TMJ neurons in cells from uninjured and inflamed rats.

Heppleman, 1997 [21]

Rat, cat, dog, monkey

Review discussing innervation of joint structures including 71 references. No mention of male or female in text.

Schaible et al., 2010 [25]

Rats, mice

Review discussing effects of cytokines on joint afferents including 55 references. No mention of male or female in text.

Schwab and Funk, 1998 [22]

Rat

Shows neuropeptide innervation of hyaline cartilage and fibrocartilage.

Stein, 1995 [34]

Rat; human; cultured cells

Review article discussing peripheral opioid effects in arthritis including 50 references; no mention of sex differences.

Suri et al., 2007 [23]

Human

Human

Shows innervation of articular cartilage in subjects with OA; no mention of sex differences.

Walsh et al., 2010 [24]

Human

Human

Shows vascularization and innervation of RA and OA joints. No mention of sex differences.