CB1 and CB2 Receptor Expression in Type 1 Diabetic Neuropathic Rats Is Enhanced by Photobiomodulation Therapy

Background: The interaction between the endocannabinoid system (ECS), specifically the CB1 and CB2 cannabinoid receptors, and neuropathy has aroused great research interest due to the possible implications for treatment. Complications following type 1 diabetes, due to impaired glucose metabolism and chronic inflammation, may benefit from targeted therapeutic strategies involving the ECS. This study explores the effects of photobiomodulation therapy (PBMT) on streptozotocin (STZ)-induced diabetic peripheral neuropathy (DPN) in rats. The study assessed body mass, hyperglycemia, mechanical hyperalgesia, and the influence of PBMT on these conditions over four weeks. Results showed that while PBMT did not alter the metabolic aspects of type I diabetes, it significantly reduced mechanical hyperalgesia compared to untreated diabetic neuropathic rats. Notably, cannabinoid receptor antagonists for CB1 and CB2 elicited a transient reversal of this antihyperalgesic effect, indicating a potential role of these receptors in PBMT’s mechanism. However, CB2 modulation was not statistically significant, whereas changes in CB1 receptor expression were observed in the dorsal root ganglia, suggesting its involvement in PBMT’s effects. These findings highlight the importance of CB1 and CB2 receptors in DPN and suggest that PBMT may offer a therapeutic benefit by mitigating mechanical hyperalgesia. Further investigation into cannabinoid receptor dynamics in diabetes could help in new therapeutic strategies for managing diabetic complications.