Table 2 PRF in animal experiments demonstrating its effect and safety

Tun et al.[26]

Histopathology and electron microscopy of rat brain tissue after RF and PRF

Reversible histological changes with PRF, while cellular necrosis seen with Cont RF

PRF is non-destructive and safe than RF

Cahana et al.[27]

Acute effects of PRF and CRF on impulse propagation and synaptic transmission in rat hippocampus

Effects of PRF less destructive and reversible. At more than 2000 μm, both RF and PRF did not affect the cellular morphology, at 1000 μm only CRF and not PRF destroyed the neuronal architecture

PRF is safer when compared to CRF; also established the clinical effects with differing distances from the RF probe

Higuchi et al.[28]

Rat DRG exposed to PRF and CRF

Only PRF led to increased C-Fos expression from the superficial laminae of the dorsal horn within 3 h after treatment

Action of PRF was demonstrated by C-Fos expression, which is speculated to be a mode of action of PRF

Erdine et al.[29]

Rat DRG exposed to CRF and PRF

Mitochondrial degeneration and loss of nuclear membrane with CRF and only cellular edema with PRF (reversible change)

Safety of PRF over CRF on DRG was demonstrated

Van Zundert et al.[30]

Rat DRG CRF and PRF applied at 67°

Demonstration of late trans-synaptic activity as C-Fos seen even after 7 days in both RF and PRF

Late cellular activity observed by PRF; indicates long-term changes effected by PRF

Podhajsky et al.[31]

CRF and PRF at 2° on rat DRG

Only endoneurial edema and collagen deposition; no irreversible changes seen

PRF depends on non destructive effects, and temperature of 42° and below are not associated with neural destruction

Hamman et al.[32]

PRF applied to axotomised DRG and sciatic nerve

Increased ATP -three positive cells with PRF of axotomised DRG and not in sciatic nerve

Selective action of PRF on Aδ and C fibers, sparing the more larger fibers

Hagiwara et al.[33]

PRF on rats with adjuvant induced hyperalgesia

PRF at 37° and 42°-successful in treating hyperalgesia, when compared to CRF and sham interventions The same effect was blocked by α-adrenoceptor blocker Yohimbine

The analgesic effect of PRF may involve descending adrenergic and serotenergic systems

Aksu et al.[34]

Rat model - induction of neuropathic pain by sciatic nerve ligation and PRF to DRG

PRF successful in decreasing the hyperalgesia associated with neuropathic pain

Efficacy of PRF in neuropathic pain

Heavner et al.[35]

Coagulation of egg white patterns with CRF and PRF applied at various temperatures

At 42°- no coagulation observed with PRF, and pattern just observed at 60°, with CRF coagulation observed even at 42°

Safety of PRF when applied at 42°

Vatansaver et al.[36]

Neurothermal effects of PRF and CRF - studied in sciatic nerve of rats, with lesions applied at 400°C, 420°C, and 800°C

No neurological deficits at temperatures less than 800°C; however at 400°C, PRF was less damaging than CRF

Relatively safety of PRF further established at less than 42°C