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Exposure to Morphine and Caffeine Induces Apoptosis and Mitochondrial Dysfunction in a Neonatal Rat Brain
Sweatha Kasala1, Seema Briyal2, Preetha Prazad1
1Division of Neonatology, Department of Pediatrics, Advocate Children's Hospital, Park Ridge, IL, United States.
Insights
The combined use of morphine and caffeine in preterm infants increases brain cell damage and apoptosis, unlike when these drugs are used alone. This study investigated the neurotoxic mechanisms of this common neonatal intensive care unit drug combination.
Area of Science:
- Neuroscience
- Pharmacology
- Developmental Biology
Background:
- Preterm infants' developing brains are vulnerable to central nervous system drugs.
- Morphine and caffeine are commonly co-administered in neonatal intensive care units for pain and apnea, respectively.
- Mechanisms underlying the neurotoxicity of this drug combination require further elucidation.
Purpose of the Study:
- To investigate the effects of morphine and caffeine, alone and in combination, on mitochondrial dysfunction, neural apoptosis, and endothelin receptor expression in neonatal rat brains.
- To determine the impact of this combination on specific markers such as Drp1, Mfn2, Bcl-2, and Bax.
Main Methods:
- Neonatal rats were administered saline, morphine, caffeine, or a combination of both from postnatal days 3-6.
- Brain tissues were analyzed at postnatal days 7, 14, and 28 using immunofluorescence and western blot.
- Evaluated markers included mitochondrial dysfunction proteins (Drp1, Mfn2), apoptosis markers (Bcl-2, Bax), and endothelin receptors (ETA, ETB).
Main Results:
- The combination of morphine and caffeine significantly increased Bax expression compared to individual drugs in both male and female pups.
- Increased expression of Drp1 and Bax, along with suppressed Mfn2 and Bcl-2, was observed across all treatment groups versus control.
- No significant differences in endothelin receptor A (ETA) or B (ETB) expression were found.
Conclusions:
- Concurrent morphine and caffeine use in early life exacerbates apoptosis and cell damage in the developing brain.
- The findings suggest potential neurotoxic mechanisms involving mitochondrial dysfunction and apoptosis pathways.
- Endothelin receptor expression does not appear to be significantly altered by this drug combination in the studied period.
Abstract:
Background: Preterm infants experience rapid brain growth during early post-natal life making them vulnerable to drugs acting on central nervous system. Morphine is administered to premature neonates for pain control and caffeine for apnea of prematurity. Simultaneous use of morphine and caffeine is common in the neonatal intensive care unit. Prior studies have shown acute neurotoxicity with this combination, however, little information is available on the mechanisms mediating the neurotoxic effects. The objective of this study was to determine the effects of morphine and caffeine, independently and in combination on mitochondrial dysfunction (Drp1 and Mfn2), neural apoptosis (Bcl-2, Bax, and cell damage) and endothelin (ET) receptors (ETA and ETB) in neonatal rat brain. Methods: Male and female rat pups were grouped separately and were divided into four different subgroups on the basis of treatments-saline (Control), morphine (MOR), caffeine (CAFF), and morphine + caffeine (M+C) treatment. Pups in MOR group were injected with 2 mg/kg morphine, CAFF group received 100 mg/kg caffeine, and M+C group received both morphine (2 mg/kg) and caffeine (100 mg/kg), subcutaneously on postnatal days (PND) 3-6. Pups were euthanized at PND 7, 14, or 28. Brains were isolated and analyzed for mitochondrial dysfunction, apoptosis markers, cell damage, and ET receptor expression via immunofluorescence and western blot analyses. Results: M+C showed a significantly higher expression of Bax compared to CAFF or MOR alone at PND 7, 14, 28 in female pups (p < 0.05) and at PND 7, 14 in male pups (p < 0.05). Significantly (p < 0.05) increased expression of Drp1, Bax, and suppressed expression of Mfn2, Bcl-2 at PND 7, 14, 28 in all the treatment groups compared to the control was observed in both genders. No significant difference in the expression of ETA and ETB receptors in male or female pups was seen at PND 7, 14, and 28. Conclusion: Concurrent use of morphine and caffeine during the first week of life increases apoptosis and cell damage in the developing brain compared to individual use of caffeine and morphine.
