The researchers investigated how hydrogen sulfide in the spinal cord affects diabetic neuropathic pain in rats. They induced diabetic neuropathic pain in rats and divided them into different groups for treatment. They found that rats with diabetic neuropathic pain had lower pain thresholds and higher levels of a specific protein and mRNA related to pain compared to normal rats. However, when the rats with diabetic neuropathic pain were treated with a substance to block hydrogen sulfide, their pain thresholds increased and the levels of the pain-related protein and mRNA decreased. This suggests that hydrogen sulfide in the spinal cord plays a role in maintaining diabetic neuropathic pain in rats.