Table 2.

PRF in animal experiments demonstrating its effect and safety

Authors	Study information	Results	Observations
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