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Exposure to Sevoflurane Affects the Development of Parvalbumin Interneurons in the Main Olfactory Bulb in Mice.

Yang J, Chen J, Cai G, Lu R, Sun T, Luo T, Wu S, Ling S - Front Neuroanat (2016)

Bottom Line: Sevoflurane is widely used in adult and pediatric patients during clinical surgeries.This study detected the effect of sevoflurane exposure on the development of calcium-binding proteins-expressing interneurons in the main olfactory bulb (MOB).We exposed neonatal mice to 2% sevoflurane at two different developmental time points and found that exposing mice to sevoflurane at postnatal day (PD) 7 significantly decreased the expression of GAD67 and parvalbumin (PV) in the olfactory bulb (OB) but did not alter the expression of calretinin (CR) or calbindin D28k (CB).

View Article: PubMed Central - PubMed

Affiliation: Institute of Neuroscience and Anatomy, School of Medicine, Zhejiang University Hangzhou, China.

ABSTRACT
Sevoflurane is widely used in adult and pediatric patients during clinical surgeries. Although studies have shown that exposure to sevoflurane impairs solfactory memory after an operation, the neuropathological changes underlying this effect are not clear. This study detected the effect of sevoflurane exposure on the development of calcium-binding proteins-expressing interneurons in the main olfactory bulb (MOB). We exposed neonatal mice to 2% sevoflurane at two different developmental time points and found that exposing mice to sevoflurane at postnatal day (PD) 7 significantly decreased the expression of GAD67 and parvalbumin (PV) in the olfactory bulb (OB) but did not alter the expression of calretinin (CR) or calbindin D28k (CB). The number and dendritic morphology of PV-expressing interneurons in the MOB were impaired by exposure to sevoflurane at PD7. However, exposure to sevoflurane at PD10 had no effect on calcium-binding protein expression or the number and dendritic morphology of PV-expressing interneurons in the MOB. These results suggest that exposing neonatal mice to sevoflurane during a critical period of olfactory development affects the development of PV-expressing interneurons in the MOB.

No MeSH data available.


Related in: MedlinePlus

The effect of exposure to sevoflurane at PD7 on the number of calcium-binding protein-expressing neurons in the MOB. Control mice (A) had more PV interneurons in the MOB than the sevoflurane-treated mice (B). (A1,B1) High magnification images of PV interneurons in the MOB. The density of CR interneurons in the MOB of mice exposed to sevoflurane at PD7 (D) was unaffected compared to the control mice (E). (D1,E1) High magnification images of CR interneurons in the MOB. The density of CB interneurons in the MOB of mice exposed to sevoflurane at PD7 (G) was unaffected compared to the control mice (H). (G1,H1) High magnification images of CB interneurons in the MOB. Normal: control group. SEV: sevoflurane-treated group. Quantification analysis of the number of PV-ir neurons (C), CR-ir neurons (F) and CB-ir neurons (I) in different layers of MOB. Scale bars = 100 μm (applies to A–H,A1–H1). Values are expressed as the Mean ± SD. ***P < 0.001.
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Figure 3: The effect of exposure to sevoflurane at PD7 on the number of calcium-binding protein-expressing neurons in the MOB. Control mice (A) had more PV interneurons in the MOB than the sevoflurane-treated mice (B). (A1,B1) High magnification images of PV interneurons in the MOB. The density of CR interneurons in the MOB of mice exposed to sevoflurane at PD7 (D) was unaffected compared to the control mice (E). (D1,E1) High magnification images of CR interneurons in the MOB. The density of CB interneurons in the MOB of mice exposed to sevoflurane at PD7 (G) was unaffected compared to the control mice (H). (G1,H1) High magnification images of CB interneurons in the MOB. Normal: control group. SEV: sevoflurane-treated group. Quantification analysis of the number of PV-ir neurons (C), CR-ir neurons (F) and CB-ir neurons (I) in different layers of MOB. Scale bars = 100 μm (applies to A–H,A1–H1). Values are expressed as the Mean ± SD. ***P < 0.001.

Mentions: To determine whether the observed molecular changes represented alterations at the cellular level, immunofluorescence staining was performed to display calcium-binding proteins in immunoreactive (ir) interneurons. The pattern of distribution for PV-ir, CR-ir and CB-ir interneurons were not qualitatively different between sevoflurane-treated mice and control mice. The soma of the PV-ir interneurons were mainly located in the EPL and few PV-ir cells located in ML and IPL. The CB-ir interneurons were periglomerular interneurons, and the CR-ir interneurons were observed in all layers of the MOB, with the highest packing density in the GL (Figures 3A–F). Quantitative estimations of PV-ir interneuronal density in the MOB in PD42 mice revealed that sevoflurane exposure at PD7 significantly decreased the number of PV-ir neurons not only in EPL but also in the ML and IPL (Figure 3G, P < 0.001 respectively). However, sevoflurane exposure at PD7 did not induce a striking change in the density of CR-ir and CB-ir interneurons compared to their numbers in the controls (Figures 3H,I).


Exposure to Sevoflurane Affects the Development of Parvalbumin Interneurons in the Main Olfactory Bulb in Mice.

Yang J, Chen J, Cai G, Lu R, Sun T, Luo T, Wu S, Ling S - Front Neuroanat (2016)

The effect of exposure to sevoflurane at PD7 on the number of calcium-binding protein-expressing neurons in the MOB. Control mice (A) had more PV interneurons in the MOB than the sevoflurane-treated mice (B). (A1,B1) High magnification images of PV interneurons in the MOB. The density of CR interneurons in the MOB of mice exposed to sevoflurane at PD7 (D) was unaffected compared to the control mice (E). (D1,E1) High magnification images of CR interneurons in the MOB. The density of CB interneurons in the MOB of mice exposed to sevoflurane at PD7 (G) was unaffected compared to the control mice (H). (G1,H1) High magnification images of CB interneurons in the MOB. Normal: control group. SEV: sevoflurane-treated group. Quantification analysis of the number of PV-ir neurons (C), CR-ir neurons (F) and CB-ir neurons (I) in different layers of MOB. Scale bars = 100 μm (applies to A–H,A1–H1). Values are expressed as the Mean ± SD. ***P < 0.001.
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Figure 3: The effect of exposure to sevoflurane at PD7 on the number of calcium-binding protein-expressing neurons in the MOB. Control mice (A) had more PV interneurons in the MOB than the sevoflurane-treated mice (B). (A1,B1) High magnification images of PV interneurons in the MOB. The density of CR interneurons in the MOB of mice exposed to sevoflurane at PD7 (D) was unaffected compared to the control mice (E). (D1,E1) High magnification images of CR interneurons in the MOB. The density of CB interneurons in the MOB of mice exposed to sevoflurane at PD7 (G) was unaffected compared to the control mice (H). (G1,H1) High magnification images of CB interneurons in the MOB. Normal: control group. SEV: sevoflurane-treated group. Quantification analysis of the number of PV-ir neurons (C), CR-ir neurons (F) and CB-ir neurons (I) in different layers of MOB. Scale bars = 100 μm (applies to A–H,A1–H1). Values are expressed as the Mean ± SD. ***P < 0.001.
Mentions: To determine whether the observed molecular changes represented alterations at the cellular level, immunofluorescence staining was performed to display calcium-binding proteins in immunoreactive (ir) interneurons. The pattern of distribution for PV-ir, CR-ir and CB-ir interneurons were not qualitatively different between sevoflurane-treated mice and control mice. The soma of the PV-ir interneurons were mainly located in the EPL and few PV-ir cells located in ML and IPL. The CB-ir interneurons were periglomerular interneurons, and the CR-ir interneurons were observed in all layers of the MOB, with the highest packing density in the GL (Figures 3A–F). Quantitative estimations of PV-ir interneuronal density in the MOB in PD42 mice revealed that sevoflurane exposure at PD7 significantly decreased the number of PV-ir neurons not only in EPL but also in the ML and IPL (Figure 3G, P < 0.001 respectively). However, sevoflurane exposure at PD7 did not induce a striking change in the density of CR-ir and CB-ir interneurons compared to their numbers in the controls (Figures 3H,I).

Bottom Line: Sevoflurane is widely used in adult and pediatric patients during clinical surgeries.This study detected the effect of sevoflurane exposure on the development of calcium-binding proteins-expressing interneurons in the main olfactory bulb (MOB).We exposed neonatal mice to 2% sevoflurane at two different developmental time points and found that exposing mice to sevoflurane at postnatal day (PD) 7 significantly decreased the expression of GAD67 and parvalbumin (PV) in the olfactory bulb (OB) but did not alter the expression of calretinin (CR) or calbindin D28k (CB).

View Article: PubMed Central - PubMed

Affiliation: Institute of Neuroscience and Anatomy, School of Medicine, Zhejiang University Hangzhou, China.

ABSTRACT
Sevoflurane is widely used in adult and pediatric patients during clinical surgeries. Although studies have shown that exposure to sevoflurane impairs solfactory memory after an operation, the neuropathological changes underlying this effect are not clear. This study detected the effect of sevoflurane exposure on the development of calcium-binding proteins-expressing interneurons in the main olfactory bulb (MOB). We exposed neonatal mice to 2% sevoflurane at two different developmental time points and found that exposing mice to sevoflurane at postnatal day (PD) 7 significantly decreased the expression of GAD67 and parvalbumin (PV) in the olfactory bulb (OB) but did not alter the expression of calretinin (CR) or calbindin D28k (CB). The number and dendritic morphology of PV-expressing interneurons in the MOB were impaired by exposure to sevoflurane at PD7. However, exposure to sevoflurane at PD10 had no effect on calcium-binding protein expression or the number and dendritic morphology of PV-expressing interneurons in the MOB. These results suggest that exposing neonatal mice to sevoflurane during a critical period of olfactory development affects the development of PV-expressing interneurons in the MOB.

No MeSH data available.


Related in: MedlinePlus